31023021221 has 16 divisors (see below), whose sum is σ = 32564784000. Its totient is φ = 29523434688.

The previous prime is 31023021199. The next prime is 31023021223. The reversal of 31023021221 is 12212032013.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31023021221 is a prime.

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 31023021221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31023021223) 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, 398711 + ... + 470123.

It is an arithmetic number, because the mean of its divisors is an integer number (2035299000).

Almost surely, 2^31023021221 is an apocalyptic number.

It is an amenable number.

31023021221 is a deficient number, since it is larger than the sum of its proper divisors (1541762779).

31023021221 is a wasteful number, since it uses less digits than its factorization.

31023021221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 71708.

The product of its (nonzero) digits is 144, while the sum is 17.

Adding to 31023021221 its reverse (12212032013), we get a palindrome (43235053234).

The spelling of 31023021221 in words is "thirty-one billion, twenty-three million, twenty-one thousand, two hundred twenty-one".