166561620 has 24 divisors (see below), whose sum is σ = 466372704. Its totient is φ = 44416416.

The previous prime is 166561613. The next prime is 166561649. The reversal of 166561620 is 26165661.

It is a congruent number.

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, 1387954 + ... + 1388073.

It is an arithmetic number, because the mean of its divisors is an integer number (19432196).

Almost surely, 2^166561620 is an apocalyptic number.

166561620 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

166561620 is an abundant number, since it is smaller than the sum of its proper divisors (299811084).

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

166561620 is a wasteful number, since it uses less digits than its factorization.

166561620 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2776039 (or 2776037 counting only the distinct ones).

The product of its (nonzero) digits is 12960, while the sum is 33.

The square root of 166561620 is about 12905.8754061861. The cubic root of 166561620 is about 550.2055650328.

The spelling of 166561620 in words is "one hundred sixty-six million, five hundred sixty-one thousand, six hundred twenty".