166724640 has 72 divisors (see below), whose sum is σ = 568952748. Its totient is φ = 44459520.

The previous prime is 166724633. The next prime is 166724641. The reversal of 166724640 is 46427661.

166724640 is a `hidden beast` number, since 1 + 6 + 6 + 7 + 2 + 4 + 640 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 163942416 + 2782224 = 12804^2 + 1668^2 .

It is a tau number, because it is divible by the number of its divisors (72).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 166724595 and 166724604.

It is not an unprimeable number, because it can be changed into a prime (166724641) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 56451 + ... + 59330.

Almost surely, 2^166724640 is an apocalyptic number.

166724640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

166724640 is an abundant number, since it is smaller than the sum of its proper divisors (402228108).

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

166724640 is a wasteful number, since it uses less digits than its factorization.

166724640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 115802 (or 115791 counting only the distinct ones).

The product of its (nonzero) digits is 48384, while the sum is 36.

The square root of 166724640 is about 12912.1895896862. The cubic root of 166724640 is about 550.3850086619.

It can be divided in two parts, 16672 and 4640, that added together give a palindrome (21312).

The spelling of 166724640 in words is "one hundred sixty-six million, seven hundred twenty-four thousand, six hundred forty".