1021400321 has 4 divisors (see below), whose sum is σ = 1021468500. Its totient is φ = 1021332144.

The previous prime is 1021400299. The next prime is 1021400339. The reversal of 1021400321 is 1230041201.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 1230041201 = 1973 ⋅623437.

It can be written as a sum of positive squares in 2 ways, for example, as 583753921 + 437646400 = 24161^2 + 20920^2 .

It is a cyclic number.

It is not a de Polignac number, because 1021400321 - 2¹⁰ = 1021399297 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1021400296 and 1021400305.

It is not an unprimeable number, because it can be changed into a prime (1021400021) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 746 + ... + 45203.

It is an arithmetic number, because the mean of its divisors is an integer number (255367125).

Almost surely, 2^1021400321 is an apocalyptic number.

It is an amenable number.

1021400321 is a deficient number, since it is larger than the sum of its proper divisors (68179).

1021400321 is an equidigital number, since it uses as much as digits as its factorization.

1021400321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 68178.

The product of its (nonzero) digits is 48, while the sum is 14.

The square root of 1021400321 is about 31959.3542018608. The cubic root of 1021400321 is about 1007.0831508510.

Adding to 1021400321 its reverse (1230041201), we get a palindrome (2251441522).

The spelling of 1021400321 in words is "one billion, twenty-one million, four hundred thousand, three hundred twenty-one".