21255551265460 has 24 divisors (see below), whose sum is σ = 44638172875296. Its totient is φ = 8501931893280.

The previous prime is 21255551265409. The next prime is 21255551265467. The reversal of 21255551265460 is 6456215555212.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21255551265467) 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, 17433906 + ... + 18613225.

It is an arithmetic number, because the mean of its divisors is an integer number (1859923869804).

Almost surely, 2^{21255551265460} is an apocalyptic number.

21255551265460 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21255551265460 is an abundant number, since it is smaller than the sum of its proper divisors (23382621609836).

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

21255551265460 is a wasteful number, since it uses less digits than its factorization.

21255551265460 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36076623 (or 36076621 counting only the distinct ones).

The product of its (nonzero) digits is 3600000, while the sum is 49.

The spelling of 21255551265460 in words is "twenty-one trillion, two hundred fifty-five billion, five hundred fifty-one million, two hundred sixty-five thousand, four hundred sixty".