31305213021 has 16 divisors (see below), whose sum is σ = 43173486720. Its totient is φ = 20163425280.

The previous prime is 31305213007. The next prime is 31305213031. The reversal of 31305213021 is 12031250313.

It is not a de Polignac number, because 31305213021 - 2¹⁰ = 31305211997 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31305213031) 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, 1222836 + ... + 1248173.

It is an arithmetic number, because the mean of its divisors is an integer number (2698342920).

Almost surely, 2^31305213021 is an apocalyptic number.

It is an amenable number.

31305213021 is a deficient number, since it is larger than the sum of its proper divisors (11868273699).

31305213021 is a wasteful number, since it uses less digits than its factorization.

31305213021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2471156.

The product of its (nonzero) digits is 540, while the sum is 21.

Adding to 31305213021 its reverse (12031250313), we get a palindrome (43336463334).

The spelling of 31305213021 in words is "thirty-one billion, three hundred five million, two hundred thirteen thousand, twenty-one".