21572051766 has 32 divisors (see below), whose sum is σ = 44666920800. Its totient is φ = 6937271040.

The previous prime is 21572051759. The next prime is 21572051783. The reversal of 21572051766 is 66715027512.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 176196 + ... + 272376.

It is an arithmetic number, because the mean of its divisors is an integer number (1395841275).

Almost surely, 2^21572051766 is an apocalyptic number.

21572051766 is an abundant number, since it is smaller than the sum of its proper divisors (23094869034).

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

21572051766 is a wasteful number, since it uses less digits than its factorization.

21572051766 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 97504.

The product of its (nonzero) digits is 176400, while the sum is 42.

The spelling of 21572051766 in words is "twenty-one billion, five hundred seventy-two million, fifty-one thousand, seven hundred sixty-six".