161855604400 has 360 divisors, whose sum is σ = 463429195776. Its totient is φ = 54150566400.

The previous prime is 161855604367. The next prime is 161855604413. The reversal of 161855604400 is 4406558161.

It is a Harshad number since it is a multiple of its sum of digits (40).

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 148900657 + ... + 148901743.

Almost surely, 2^161855604400 is an apocalyptic number.

161855604400 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 161855604400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (231714597888).

161855604400 is an abundant number, since it is smaller than the sum of its proper divisors (301573591376).

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

161855604400 is a wasteful number, since it uses less digits than its factorization.

161855604400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1297 (or 1279 counting only the distinct ones).

The product of its (nonzero) digits is 115200, while the sum is 40.

The spelling of 161855604400 in words is "one hundred sixty-one billion, eight hundred fifty-five million, six hundred four thousand, four hundred".