21165540152066 has 8 divisors (see below), whose sum is σ = 31748394686844. Its totient is φ = 10582741923120.

The previous prime is 21165540151993. The next prime is 21165540152077. The reversal of 21165540152066 is 66025104556112.

It can be written as a sum of positive squares in 2 ways, for example, as 20088583956841 + 1076956195225 = 4482029^2 + 1037765^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13123805 + ... + 14648048.

Almost surely, 2^{21165540152066} is an apocalyptic number.

21165540152066 is a deficient number, since it is larger than the sum of its proper divisors (10582854534778).

21165540152066 is a wasteful number, since it uses less digits than its factorization.

21165540152066 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28152916.

The product of its (nonzero) digits is 432000, while the sum is 44.

The spelling of 21165540152066 in words is "twenty-one trillion, one hundred sixty-five billion, five hundred forty million, one hundred fifty-two thousand, sixty-six".