1021252421 has 4 divisors (see below), whose sum is σ = 1167145632. Its totient is φ = 875359212.

The previous prime is 1021252409. The next prime is 1021252433. The reversal of 1021252421 is 1242521201.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 1242521201 = 21799 ⋅56999.

It is an interprime number because it is at equal distance from previous prime (1021252409) and next prime (1021252433).

It is not a de Polignac number, because 1021252421 - 2⁶ = 1021252357 is a prime.

It is a super-2 number, since 2×1021252421² = 2085913014796722482, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1021252393 and 1021252402.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1021252121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 72946595 + ... + 72946608.

It is an arithmetic number, because the mean of its divisors is an integer number (291786408).

Almost surely, 2^1021252421 is an apocalyptic number.

It is an amenable number.

1021252421 is a deficient number, since it is larger than the sum of its proper divisors (145893211).

1021252421 is an equidigital number, since it uses as much as digits as its factorization.

1021252421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 145893210.

The product of its (nonzero) digits is 320, while the sum is 20.

The square root of 1021252421 is about 31957.0402415493. The cubic root of 1021252421 is about 1007.0345395525.

Adding to 1021252421 its reverse (1242521201), we get a palindrome (2263773622).

The spelling of 1021252421 in words is "one billion, twenty-one million, two hundred fifty-two thousand, four hundred twenty-one".