31211220021 has 8 divisors (see below), whose sum is σ = 41627362560. Its totient is φ = 20801278752.

The previous prime is 31211219999. The next prime is 31211220037. The reversal of 31211220021 is 12002211213.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 31211220021 - 2¹⁵ = 31211187253 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31211210021) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1538560 + ... + 1558713.

It is an arithmetic number, because the mean of its divisors is an integer number (5203420320).

Almost surely, 2^31211220021 is an apocalyptic number.

It is an amenable number.

31211220021 is a deficient number, since it is larger than the sum of its proper divisors (10416142539).

31211220021 is a wasteful number, since it uses less digits than its factorization.

31211220021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3100635.

The product of its (nonzero) digits is 48, while the sum is 15.

Adding to 31211220021 its reverse (12002211213), we get a palindrome (43213431234).

The spelling of 31211220021 in words is "thirty-one billion, two hundred eleven million, two hundred twenty thousand, twenty-one".