21255332550 has 24 divisors (see below), whose sum is σ = 52713225096. Its totient is φ = 5668088640.

The previous prime is 21255332531. The next prime is 21255332561. The reversal of 21255332550 is 5523355212.

It is a super-2 number, since 2×21255332550² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 70850959 + ... + 70851258.

It is an arithmetic number, because the mean of its divisors is an integer number (2196384379).

Almost surely, 2^21255332550 is an apocalyptic number.

21255332550 is an abundant number, since it is smaller than the sum of its proper divisors (31457892546).

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

21255332550 is a wasteful number, since it uses less digits than its factorization.

21255332550 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 141702232 (or 141702227 counting only the distinct ones).

The product of its (nonzero) digits is 45000, while the sum is 33.

Adding to 21255332550 its reverse (5523355212), we get a palindrome (26778687762).

The spelling of 21255332550 in words is "twenty-one billion, two hundred fifty-five million, three hundred thirty-two thousand, five hundred fifty".