1321131021 has 16 divisors (see below), whose sum is σ = 2013731328. Its totient is φ = 754714800.

The previous prime is 1321131001. The next prime is 1321131023. The reversal of 1321131021 is 1201311231.

It is a happy number.

It is not a de Polignac number, because 1321131021 - 2⁷ = 1321130893 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1321131023) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 91806 + ... + 105216.

It is an arithmetic number, because the mean of its divisors is an integer number (125858208).

Almost surely, 2^1321131021 is an apocalyptic number.

It is an amenable number.

1321131021 is a deficient number, since it is larger than the sum of its proper divisors (692600307).

1321131021 is a wasteful number, since it uses less digits than its factorization.

1321131021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18112.

The product of its (nonzero) digits is 36, while the sum is 15.

The square root of 1321131021 is about 36347.3660806392. The cubic root of 1321131021 is about 1097.2745256615.

Adding to 1321131021 its reverse (1201311231), we get a palindrome (2522442252).

The spelling of 1321131021 in words is "one billion, three hundred twenty-one million, one hundred thirty-one thousand, twenty-one".