21260665044 has 36 divisors (see below), whose sum is σ = 53797333044. Its totient is φ = 7079622912.

The previous prime is 21260665031. The next prime is 21260665109. The reversal of 21260665044 is 44056606212.

21260665044 is a `hidden beast` number, since 2 + 1 + 2 + 606 + 6 + 5 + 0 + 44 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 17822250000 + 3438415044 = 133500^2 + 58638^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a super-2 number, since 2×21260665044² (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 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, 267067 + ... + 337410.

Almost surely, 2^21260665044 is an apocalyptic number.

It is an amenable number.

21260665044 is an abundant number, since it is smaller than the sum of its proper divisors (32536668000).

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

21260665044 is a wasteful number, since it uses less digits than its factorization.

21260665044 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 605464 (or 605459 counting only the distinct ones).

The product of its (nonzero) digits is 69120, while the sum is 36.

The spelling of 21260665044 in words is "twenty-one billion, two hundred sixty million, six hundred sixty-five thousand, forty-four".