166621920 has 48 divisors (see below), whose sum is σ = 524860560. Its totient is φ = 44432384.

The previous prime is 166621891. The next prime is 166621921. The reversal of 166621920 is 29126661.

It is a tau number, because it is divible by the number of its divisors (48).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (166621921) 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, 173085 + ... + 174044.

It is an arithmetic number, because the mean of its divisors is an integer number (10934595).

Almost surely, 2^166621920 is an apocalyptic number.

166621920 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

166621920 is an abundant number, since it is smaller than the sum of its proper divisors (358238640).

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

166621920 is a wasteful number, since it uses less digits than its factorization.

166621920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 347147 (or 347139 counting only the distinct ones).

The product of its (nonzero) digits is 7776, while the sum is 33.

The square root of 166621920 is about 12908.2113400734. The cubic root of 166621920 is about 550.2719536616.

The spelling of 166621920 in words is "one hundred sixty-six million, six hundred twenty-one thousand, nine hundred twenty".