161639370 has 48 divisors (see below), whose sum is σ = 424143720. Its totient is φ = 42705792.

The previous prime is 161639353. The next prime is 161639389. The reversal of 161639370 is 73936161.

161639370 is a `hidden beast` number, since 1 + 616 + 3 + 9 + 37 + 0 = 666.

161639370 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 131400369 + 30239001 = 11463^2 + 5499^2 .

It is a super-2 number, since 2×161639370² = 52254571867993800, which contains 22 as substring.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1572 + ... + 18048.

Almost surely, 2^161639370 is an apocalyptic number.

161639370 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 161639370, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (212071860).

161639370 is an abundant number, since it is smaller than the sum of its proper divisors (262504350).

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

161639370 is a wasteful number, since it uses less digits than its factorization.

161639370 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16599 (or 16596 counting only the distinct ones).

The product of its (nonzero) digits is 20412, while the sum is 36.

The square root of 161639370 is about 12713.7472839443. The cubic root of 161639370 is about 544.7313660814.

The spelling of 161639370 in words is "one hundred sixty-one million, six hundred thirty-nine thousand, three hundred seventy".