166645717745551 has 32 divisors (see below), whose sum is σ = 194480654538240. Its totient is φ = 141262643596800.

The previous prime is 166645717745519. The next prime is 166645717745581. The reversal of 166645717745551 is 155547717546661.

It is not a de Polignac number, because 166645717745551 - 2⁵ = 166645717745519 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (166645717745581) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 6679411 + ... + 19439803.

It is an arithmetic number, because the mean of its divisors is an integer number (6077520454320).

Almost surely, 2^{166645717745551} is an apocalyptic number.

166645717745551 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

166645717745551 is a deficient number, since it is larger than the sum of its proper divisors (27834936792689).

166645717745551 is a wasteful number, since it uses less digits than its factorization.

166645717745551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12761727.

The product of its digits is 740880000, while the sum is 70.

The spelling of 166645717745551 in words is "one hundred sixty-six trillion, six hundred forty-five billion, seven hundred seventeen million, seven hundred forty-five thousand, five hundred fifty-one".