21642561006 has 16 divisors (see below), whose sum is σ = 47220133248. Its totient is φ = 6558351800.

The previous prime is 21642560977. The next prime is 21642561011. The reversal of 21642561006 is 60016524612.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 163958730 + ... + 163958861.

It is an arithmetic number, because the mean of its divisors is an integer number (2951258328).

Almost surely, 2^21642561006 is an apocalyptic number.

21642561006 is an abundant number, since it is smaller than the sum of its proper divisors (25577572242).

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

21642561006 is a wasteful number, since it uses less digits than its factorization.

21642561006 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 327917607.

The product of its (nonzero) digits is 17280, while the sum is 33.

The spelling of 21642561006 in words is "twenty-one billion, six hundred forty-two million, five hundred sixty-one thousand, six".