172661580 has 288 divisors, whose sum is σ = 657506304. Its totient is φ = 35707392.

The previous prime is 172661561. The next prime is 172661581. The reversal of 172661580 is 85166271.

172661580 is a `hidden beast` number, since 1 + 72 + 6 + 6 + 1 + 580 = 666.

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

It is not an unprimeable number, because it can be changed into a prime (172661581) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 1359477 + ... + 1359603.

It is an arithmetic number, because the mean of its divisors is an integer number (2283008).

Almost surely, 2^172661580 is an apocalyptic number.

172661580 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 172661580, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (328753152).

172661580 is an abundant number, since it is smaller than the sum of its proper divisors (484844724).

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

172661580 is a wasteful number, since it uses less digits than its factorization.

172661580 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 245 (or 240 counting only the distinct ones).

The product of its (nonzero) digits is 20160, while the sum is 36.

The square root of 172661580 is about 13140.0753422498. The cubic root of 172661580 is about 556.8418960622.

The spelling of 172661580 in words is "one hundred seventy-two million, six hundred sixty-one thousand, five hundred eighty".