161728725 has 12 divisors (see below), whose sum is σ = 267391616. Its totient is φ = 86255280.

The previous prime is 161728717. The next prime is 161728733. The reversal of 161728725 is 527827161.

161728725 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (161728717) and next prime (161728733).

It is not a de Polignac number, because 161728725 - 2³ = 161728717 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1078117 + ... + 1078266.

Almost surely, 2^161728725 is an apocalyptic number.

161728725 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

161728725 is a deficient number, since it is larger than the sum of its proper divisors (105662891).

161728725 is a wasteful number, since it uses less digits than its factorization.

161728725 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2156396 (or 2156391 counting only the distinct ones).

The product of its digits is 47040, while the sum is 39.

The square root of 161728725 is about 12717.2609079157. The cubic root of 161728725 is about 544.8317242734.

The spelling of 161728725 in words is "one hundred sixty-one million, seven hundred twenty-eight thousand, seven hundred twenty-five".