161640540 has 72 divisors (see below), whose sum is σ = 491972208. Its totient is φ = 42958080.

The previous prime is 161640529. The next prime is 161640587. The reversal of 161640540 is 45046161.

161640540 is a `hidden beast` number, since 1 + 61 + 64 + 0 + 540 = 666.

It is a super-2 number, since 2×161640540² = 52255328342983200, which contains 22 as substring.

It is a congruent 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, 58224 + ... + 60936.

Almost surely, 2^161640540 is an apocalyptic number.

161640540 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 161640540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (245986104).

161640540 is an abundant number, since it is smaller than the sum of its proper divisors (330331668).

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

161640540 is a wasteful number, since it uses less digits than its factorization.

161640540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3059 (or 3054 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 27.

The square root of 161640540 is about 12713.7932970455. The cubic root of 161640540 is about 544.7326803943.

The spelling of 161640540 in words is "one hundred sixty-one million, six hundred forty thousand, five hundred forty".