161615720 has 48 divisors (see below), whose sum is σ = 423009540. Its totient is φ = 55410432.

The previous prime is 161615711. The next prime is 161615747. The reversal of 161615720 is 27516161.

It can be written as a sum of positive squares in 2 ways, for example, as 159112996 + 2502724 = 12614^2 + 1582^2 .

It is a super-2 number, since 2×161615720² = 52239281902236800, which contains 22 as substring.

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, 39269 + ... + 43188.

Almost surely, 2^161615720 is an apocalyptic number.

161615720 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

161615720 is an abundant number, since it is smaller than the sum of its proper divisors (261393820).

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

161615720 is a wasteful number, since it uses less digits than its factorization.

161615720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 82482 (or 82471 counting only the distinct ones).

The product of its (nonzero) digits is 2520, while the sum is 29.

The square root of 161615720 is about 12712.8171543525. The cubic root of 161615720 is about 544.7047976260.

The spelling of 161615720 in words is "one hundred sixty-one million, six hundred fifteen thousand, seven hundred twenty".