161557440 has 112 divisors (see below), whose sum is σ = 559612800. Its totient is φ = 39162880.

The previous prime is 161557433. The next prime is 161557441. The reversal of 161557440 is 44755161.

It is a super-2 number, since 2×161557440² = 52201612838707200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161557441) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2911 + ... + 18209.

Almost surely, 2^161557440 is an apocalyptic number.

161557440 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 161557440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (279806400).

161557440 is an abundant number, since it is smaller than the sum of its proper divisors (398055360).

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

161557440 is a wasteful number, since it uses less digits than its factorization.

161557440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15330 (or 15320 counting only the distinct ones).

The product of its (nonzero) digits is 16800, while the sum is 33.

The square root of 161557440 is about 12710.5247728015. The cubic root of 161557440 is about 544.6393146968.

The spelling of 161557440 in words is "one hundred sixty-one million, five hundred fifty-seven thousand, four hundred forty".