21585820157 has 16 divisors (see below), whose sum is σ = 23609491200. Its totient is φ = 19572450240.

The previous prime is 21585820133. The next prime is 21585820169. The reversal of 21585820157 is 75102858512.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 21585820157 - 2⁶ = 21585820093 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21585820117) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 12629819 + ... + 12631527.

It is an arithmetic number, because the mean of its divisors is an integer number (1475593200).

Almost surely, 2^21585820157 is an apocalyptic number.

It is an amenable number.

21585820157 is a deficient number, since it is larger than the sum of its proper divisors (2023671043).

21585820157 is a wasteful number, since it uses less digits than its factorization.

21585820157 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4036.

The product of its (nonzero) digits is 224000, while the sum is 44.

The spelling of 21585820157 in words is "twenty-one billion, five hundred eighty-five million, eight hundred twenty thousand, one hundred fifty-seven".