21211312031 has 24 divisors (see below), whose sum is σ = 26594026704. Its totient is φ = 16768926720.

The previous prime is 21211312021. The next prime is 21211312081. The reversal of 21211312031 is 13021311212.

It is not a de Polignac number, because 21211312031 - 2³⁰ = 20137570207 is a prime.

It is a super-2 number, since 2×21211312031² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21211312021) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 809471 + ... + 835263.

It is an arithmetic number, because the mean of its divisors is an integer number (1108084446).

Almost surely, 2^21211312031 is an apocalyptic number.

21211312031 is a deficient number, since it is larger than the sum of its proper divisors (5382714673).

21211312031 is a wasteful number, since it uses less digits than its factorization.

21211312031 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27111 (or 27104 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 17.

Adding to 21211312031 its reverse (13021311212), we get a palindrome (34232623243).

The spelling of 21211312031 in words is "twenty-one billion, two hundred eleven million, three hundred twelve thousand, thirty-one".