1321312012021 has 4 divisors (see below), whose sum is σ = 1321324571232. Its totient is φ = 1321299452812.

The previous prime is 1321312012003. The next prime is 1321312012067. The reversal of 1321312012021 is 1202102131231.

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 1321312012021 - 2⁵ = 1321312011989 is a prime.

It is a super-2 number, since 2×1321312012021² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1321312012021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1321312012001) 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, 6120451 + ... + 6332656.

It is an arithmetic number, because the mean of its divisors is an integer number (330331142808).

Almost surely, 2^{1321312012021} is an apocalyptic number.

It is an amenable number.

1321312012021 is a deficient number, since it is larger than the sum of its proper divisors (12559211).

1321312012021 is a wasteful number, since it uses less digits than its factorization.

1321312012021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12559210.

The product of its (nonzero) digits is 144, while the sum is 19.

Adding to 1321312012021 its reverse (1202102131231), we get a palindrome (2523414143252).

The spelling of 1321312012021 in words is "one trillion, three hundred twenty-one billion, three hundred twelve million, twelve thousand, twenty-one".