1021252021 has 4 divisors (see below), whose sum is σ = 1045002112. Its totient is φ = 997501932.

The previous prime is 1021252007. The next prime is 1021252031. The reversal of 1021252021 is 1202521201.

It is a happy number.

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.

It is a cyclic number.

It is not a de Polignac number, because 1021252021 - 2⁷ = 1021251893 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1021251986 and 1021252004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1021252031) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11874981 + ... + 11875066.

It is an arithmetic number, because the mean of its divisors is an integer number (261250528).

Almost surely, 2^1021252021 is an apocalyptic number.

It is an amenable number.

1021252021 is a deficient number, since it is larger than the sum of its proper divisors (23750091).

1021252021 is an equidigital number, since it uses as much as digits as its factorization.

1021252021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23750090.

The product of its (nonzero) digits is 80, while the sum is 16.

The square root of 1021252021 is about 31957.0339831468. The cubic root of 1021252021 is about 1007.0344080754.

Adding to 1021252021 its reverse (1202521201), we get a palindrome (2223773222).

The spelling of 1021252021 in words is "one billion, twenty-one million, two hundred fifty-two thousand, twenty-one".