166561840 has 40 divisors (see below), whose sum is σ = 388019808. Its totient is φ = 66493440.

The previous prime is 166561831. The next prime is 166561859. The reversal of 166561840 is 48165661.

166561840 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (40).

It is a self number, because there is not a number n which added to its sum of digits gives 166561840.

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, 45685 + ... + 49195.

Almost surely, 2^166561840 is an apocalyptic number.

166561840 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

166561840 is an abundant number, since it is smaller than the sum of its proper divisors (221457968).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

166561840 is a wasteful number, since it uses less digits than its factorization.

166561840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4117 (or 4111 counting only the distinct ones).

The product of its (nonzero) digits is 34560, while the sum is 37.

The square root of 166561840 is about 12905.8839294331. The cubic root of 166561840 is about 550.2058072759.

It can be divided in two parts, 16656 and 1840, that added together give a square (18496 = 136²).

The spelling of 166561840 in words is "one hundred sixty-six million, five hundred sixty-one thousand, eight hundred forty".