166621530536565 has 32 divisors (see below), whose sum is σ = 299584397387520. Its totient is φ = 78462580263936.

The previous prime is 166621530536477. The next prime is 166621530536597. The reversal of 166621530536565 is 565635035126661.

It is not a de Polignac number, because 166621530536565 - 2²² = 166621526342261 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 166621530536499 and 166621530536508.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 18575416980 + ... + 18575425949.

It is an arithmetic number, because the mean of its divisors is an integer number (9362012418360).

Almost surely, 2^{166621530536565} is an apocalyptic number.

166621530536565 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

166621530536565 is a deficient number, since it is larger than the sum of its proper divisors (132962866850955).

166621530536565 is a wasteful number, since it uses less digits than its factorization.

166621530536565 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37150842973.

The product of its (nonzero) digits is 87480000, while the sum is 60.

The spelling of 166621530536565 in words is "one hundred sixty-six trillion, six hundred twenty-one billion, five hundred thirty million, five hundred thirty-six thousand, five hundred sixty-five".