166561524 has 72 divisors (see below), whose sum is σ = 447763680. Its totient is φ = 52056000.

The previous prime is 166561523. The next prime is 166561553. The reversal of 166561524 is 425165661.

166561524 is a `hidden beast` number, since 16 + 6 + 5 + 615 + 24 = 666.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (166561523) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 67879 + ... + 70289.

It is an arithmetic number, because the mean of its divisors is an integer number (6218940).

Almost surely, 2^166561524 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 166561524, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (223881840).

166561524 is an abundant number, since it is smaller than the sum of its proper divisors (281202156).

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

166561524 is a wasteful number, since it uses less digits than its factorization.

166561524 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2541 (or 2536 counting only the distinct ones).

The product of its digits is 43200, while the sum is 36.

The square root of 166561524 is about 12905.8716869493. The cubic root of 166561524 is about 550.2054593267.

The spelling of 166561524 in words is "one hundred sixty-six million, five hundred sixty-one thousand, five hundred twenty-four".