21506672142556 has 6 divisors (see below), whose sum is σ = 37636676249480. Its totient is φ = 10753336071276.

The previous prime is 21506672142547. The next prime is 21506672142581. The reversal of 21506672142556 is 65524127660512.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2688334017816 + ... + 2688334017823.

Almost surely, 2^{21506672142556} is an apocalyptic number.

It is an amenable number.

21506672142556 is a deficient number, since it is larger than the sum of its proper divisors (16130004106924).

21506672142556 is a wasteful number, since it uses less digits than its factorization.

21506672142556 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5376668035643 (or 5376668035641 counting only the distinct ones).

The product of its (nonzero) digits is 6048000, while the sum is 52.

The spelling of 21506672142556 in words is "twenty-one trillion, five hundred six billion, six hundred seventy-two million, one hundred forty-two thousand, five hundred fifty-six".