31203120021 has 16 divisors (see below), whose sum is σ = 41873475264. Its totient is φ = 20667700224.

The previous prime is 31203120017. The next prime is 31203120041. The reversal of 31203120021 is 12002130213.

It is not a de Polignac number, because 31203120021 - 2² = 31203120017 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31203120001) 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, 421435 + ... + 489911.

It is an arithmetic number, because the mean of its divisors is an integer number (2617092204).

Almost surely, 2^31203120021 is an apocalyptic number.

It is an amenable number.

31203120021 is a deficient number, since it is larger than the sum of its proper divisors (10670355243).

31203120021 is a wasteful number, since it uses less digits than its factorization.

31203120021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 69460.

The product of its (nonzero) digits is 72, while the sum is 15.

Adding to 31203120021 its reverse (12002130213), we get a palindrome (43205250234).

The spelling of 31203120021 in words is "thirty-one billion, two hundred three million, one hundred twenty thousand, twenty-one".