21521554344 has 24 divisors (see below), whose sum is σ = 58287543210. Its totient is φ = 7173851424.

The previous prime is 21521554333. The next prime is 21521554403. The reversal of 21521554344 is 44345512512.

21521554344 is a `hidden beast` number, since 2 + 1 + 5 + 215 + 5 + 434 + 4 = 666.

It can be written as a sum of positive squares in only one way, i.e., 12274424100 + 9247130244 = 110790^2 + 96162^2 .

It is a tau number, because it is divible by the number of its divisors (24).

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 = 21521554299 and 21521554308.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 149455167 + ... + 149455310.

Almost surely, 2^21521554344 is an apocalyptic number.

21521554344 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21521554344 is an abundant number, since it is smaller than the sum of its proper divisors (36765988866).

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

21521554344 is a wasteful number, since it uses less digits than its factorization.

21521554344 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 298910489 (or 298910482 counting only the distinct ones).

The product of its digits is 96000, while the sum is 36.

The spelling of 21521554344 in words is "twenty-one billion, five hundred twenty-one million, five hundred fifty-four thousand, three hundred forty-four".