21311020254 has 16 divisors (see below), whose sum is σ = 44475172992. Its totient is φ = 6794818008.

The previous prime is 21311020253. The next prime is 21311020309. The reversal of 21311020254 is 45202011312.

It is a self number, because there is not a number n which added to its sum of digits gives 21311020254.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21311020253) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 77213704 + ... + 77213979.

It is an arithmetic number, because the mean of its divisors is an integer number (2779698312).

Almost surely, 2^21311020254 is an apocalyptic number.

21311020254 is an abundant number, since it is smaller than the sum of its proper divisors (23164152738).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21311020254 is a wasteful number, since it uses less digits than its factorization.

21311020254 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 154427711.

The product of its (nonzero) digits is 480, while the sum is 21.

Adding to 21311020254 its reverse (45202011312), we get a palindrome (66513031566).

The spelling of 21311020254 in words is "twenty-one billion, three hundred eleven million, twenty thousand, two hundred fifty-four".