166212561 has 8 divisors (see below), whose sum is σ = 222731200. Its totient is φ = 110251152.

The previous prime is 166212533. The next prime is 166212583. The reversal of 166212561 is 165212661.

166212561 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is not a de Polignac number, because 166212561 - 2⁷ = 166212433 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (166212511) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 138610 + ... + 139803.

It is an arithmetic number, because the mean of its divisors is an integer number (27841400).

Almost surely, 2^166212561 is an apocalyptic number.

It is an amenable number.

166212561 is a deficient number, since it is larger than the sum of its proper divisors (56518639).

166212561 is a wasteful number, since it uses less digits than its factorization.

166212561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 278615.

The product of its digits is 4320, while the sum is 30.

The square root of 166212561 is about 12892.3450543336. The cubic root of 166212561 is about 549.8209455713.

The spelling of 166212561 in words is "one hundred sixty-six million, two hundred twelve thousand, five hundred sixty-one".