21164805678530 has 16 divisors (see below), whose sum is σ = 38374727962680. Its totient is φ = 8404127217792.

The previous prime is 21164805678521. The next prime is 21164805678587. The reversal of 21164805678530 is 3587650846112.

It can be written as a sum of positive squares in 4 ways, for example, as 18822139725601 + 2342665952929 = 4338449^2 + 1530577^2 .

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, 7724380265 + ... + 7724383004.

Almost surely, 2^{21164805678530} is an apocalyptic number.

21164805678530 is a deficient number, since it is larger than the sum of its proper divisors (17209922284150).

21164805678530 is a wasteful number, since it uses less digits than its factorization.

21164805678530 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15448763413.

The product of its (nonzero) digits is 9676800, while the sum is 56.

The spelling of 21164805678530 in words is "twenty-one trillion, one hundred sixty-four billion, eight hundred five million, six hundred seventy-eight thousand, five hundred thirty".