172157720 has 32 divisors (see below), whose sum is σ = 442692000. Its totient is φ = 59025408.

The previous prime is 172157719. The next prime is 172157743. The reversal of 172157720 is 27751271.

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, 307145 + ... + 307704.

It is an arithmetic number, because the mean of its divisors is an integer number (13834125).

Almost surely, 2^172157720 is an apocalyptic number.

172157720 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

172157720 is an abundant number, since it is smaller than the sum of its proper divisors (270534280).

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

172157720 is a wasteful number, since it uses less digits than its factorization.

172157720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 614867 (or 614863 counting only the distinct ones).

The product of its (nonzero) digits is 6860, while the sum is 32.

The square root of 172157720 is about 13120.8886894143. Note that the first 3 decimals coincide. The cubic root of 172157720 is about 556.2997107448.

The spelling of 172157720 in words is "one hundred seventy-two million, one hundred fifty-seven thousand, seven hundred twenty".