166621655651210 has 16 divisors (see below), whose sum is σ = 300014587171656. Its totient is φ = 66627416260608.

The previous prime is 166621655651173. The next prime is 166621655651251. The reversal of 166621655651210 is 12156556126661.

It can be written as a sum of positive squares in 4 ways, for example, as 165911170183801 + 710485467409 = 12880651^2 + 842903^2 .

It is a super-2 number, since 2×166621655651210² (a number of 29 digits) contains 22 as substring.

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, 2655717047 + ... + 2655779786.

Almost surely, 2^{166621655651210} is an apocalyptic number.

166621655651210 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

166621655651210 is a deficient number, since it is larger than the sum of its proper divisors (133392931520446).

166621655651210 is a wasteful number, since it uses less digits than its factorization.

166621655651210 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5311499977.

The product of its (nonzero) digits is 3888000, while the sum is 53.

The spelling of 166621655651210 in words is "one hundred sixty-six trillion, six hundred twenty-one billion, six hundred fifty-five million, six hundred fifty-one thousand, two hundred ten".