161617680 has 300 divisors, whose sum is σ = 654249420. Its totient is φ = 36868608.

The previous prime is 161617669. The next prime is 161617699. The reversal of 161617680 is 86716161.

It can be written as a sum of positive squares in 2 ways, for example, as 96589584 + 65028096 = 9828^2 + 8064^2 .

It is a super-2 number, since 2×161617680² = 52240548977164800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 59 ways as a sum of consecutive naturals, for example, 317266 + ... + 317774.

Almost surely, 2^161617680 is an apocalyptic number.

161617680 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 161617680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (327124710).

161617680 is an abundant number, since it is smaller than the sum of its proper divisors (492631740).

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

161617680 is a wasteful number, since it uses less digits than its factorization.

161617680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 548 (or 526 counting only the distinct ones).

The product of its (nonzero) digits is 12096, while the sum is 36.

The square root of 161617680 is about 12712.8942416745. The cubic root of 161617680 is about 544.7069995922.

The spelling of 161617680 in words is "one hundred sixty-one million, six hundred seventeen thousand, six hundred eighty".