21056605344 has 96 divisors (see below), whose sum is σ = 62456184000. Its totient is φ = 6899887872.

The previous prime is 21056605333. The next prime is 21056605417. The reversal of 21056605344 is 44350665012.

21056605344 is a `hidden beast` number, since 2 + 1 + 0 + 5 + 6 + 605 + 3 + 44 = 666.

It is a tau number, because it is divible by the number of its divisors (96).

It is a super-2 number, since 2×21056605344² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 21056605299 and 21056605308.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 155559 + ... + 257510.

It is an arithmetic number, because the mean of its divisors is an integer number (650585250).

Almost surely, 2^21056605344 is an apocalyptic number.

21056605344 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21056605344 is an abundant number, since it is smaller than the sum of its proper divisors (41399578656).

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

21056605344 is a wasteful number, since it uses less digits than its factorization.

21056605344 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 413147 (or 413133 counting only the distinct ones).

The product of its (nonzero) digits is 86400, while the sum is 36.

The spelling of 21056605344 in words is "twenty-one billion, fifty-six million, six hundred five thousand, three hundred forty-four".