21506672142555 has 16 divisors (see below), whose sum is σ = 34715194682400. Its totient is φ = 11368718724608.

The previous prime is 21506672142547. The next prime is 21506672142581. The reversal of 21506672142555 is 55524127660512.

It is a cyclic number.

It is not a de Polignac number, because 21506672142555 - 2³ = 21506672142547 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21506672142498 and 21506672142507.

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, 6344149380 + ... + 6344152769.

It is an arithmetic number, because the mean of its divisors is an integer number (2169699667650).

Almost surely, 2^{21506672142555} is an apocalyptic number.

21506672142555 is a deficient number, since it is larger than the sum of its proper divisors (13208522539845).

21506672142555 is a wasteful number, since it uses less digits than its factorization.

21506672142555 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12688302270.

The product of its (nonzero) digits is 5040000, while the sum is 51.

The spelling of 21506672142555 in words is "twenty-one trillion, five hundred six billion, six hundred seventy-two million, one hundred forty-two thousand, five hundred fifty-five".