21313116550 has 48 divisors (see below), whose sum is σ = 43325923392. Its totient is φ = 7735946400.

The previous prime is 21313116523. The next prime is 21313116581. The reversal of 21313116550 is 5561131312.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 265429 + ... + 336271.

It is an arithmetic number, because the mean of its divisors is an integer number (902623404).

Almost surely, 2^21313116550 is an apocalyptic number.

21313116550 is an abundant number, since it is smaller than the sum of its proper divisors (22012806842).

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

21313116550 is a wasteful number, since it uses less digits than its factorization.

21313116550 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 71413 (or 71408 counting only the distinct ones).

The product of its (nonzero) digits is 2700, while the sum is 28.

Adding to 21313116550 its reverse (5561131312), we get a palindrome (26874247862).

The spelling of 21313116550 in words is "twenty-one billion, three hundred thirteen million, one hundred sixteen thousand, five hundred fifty".