21355577365740 has 96 divisors (see below), whose sum is σ = 60378221729280. Its totient is φ = 5639338215936.

The previous prime is 21355577365739. The next prime is 21355577365751. The reversal of 21355577365740 is 4756377555312.

It is a Smith number, since the sum of its digits (60) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (60).

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 327612471 + ... + 327677649.

It is an arithmetic number, because the mean of its divisors is an integer number (628939809680).

Almost surely, 2^{21355577365740} is an apocalyptic number.

21355577365740 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21355577365740 is an abundant number, since it is smaller than the sum of its proper divisors (39022644363540).

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

21355577365740 is a wasteful number, since it uses less digits than its factorization.

21355577365740 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 118311 (or 118309 counting only the distinct ones).

The product of its (nonzero) digits is 92610000, while the sum is 60.

The spelling of 21355577365740 in words is "twenty-one trillion, three hundred fifty-five billion, five hundred seventy-seven million, three hundred sixty-five thousand, seven hundred forty".