161690240 has 32 divisors (see below), whose sum is σ = 386542260. Its totient is φ = 64675840.

The previous prime is 161690239. The next prime is 161690257. The reversal of 161690240 is 42096161.

It can be written as a sum of positive squares in 2 ways, for example, as 138109504 + 23580736 = 11752^2 + 4856^2 .

It is a tau number, because it is divible by the number of its divisors (32).

It is a super-2 number, since 2×161690240² = 52287467422515200, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 125681 + ... + 126960.

Almost surely, 2^161690240 is an apocalyptic number.

161690240 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

161690240 is an abundant number, since it is smaller than the sum of its proper divisors (224852020).

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

161690240 is an equidigital number, since it uses as much as digits as its factorization.

161690240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 252660 (or 252648 counting only the distinct ones).

The product of its (nonzero) digits is 2592, while the sum is 29.

The square root of 161690240 is about 12715.7477169060. The cubic root of 161690240 is about 544.7885047561.

The spelling of 161690240 in words is "one hundred sixty-one million, six hundred ninety thousand, two hundred forty".