21031020311 has 16 divisors (see below), whose sum is σ = 24395397120. Its totient is φ = 17758128960.

The previous prime is 21031020287. The next prime is 21031020317. The reversal of 21031020311 is 11302013012.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21031020311 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21031020317) 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, 106550 + ... + 231116.

It is an arithmetic number, because the mean of its divisors is an integer number (1524712320).

Almost surely, 2^21031020311 is an apocalyptic number.

21031020311 is a deficient number, since it is larger than the sum of its proper divisors (3364376809).

21031020311 is a wasteful number, since it uses less digits than its factorization.

21031020311 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 124934.

The product of its (nonzero) digits is 36, while the sum is 14.

Adding to 21031020311 its reverse (11302013012), we get a palindrome (32333033323).

The spelling of 21031020311 in words is "twenty-one billion, thirty-one million, twenty thousand, three hundred eleven".