161621543580 has 96 divisors (see below), whose sum is σ = 533872496640. Its totient is φ = 35750384640.

The previous prime is 161621543569. The next prime is 161621543593. The reversal of 161621543580 is 85345126161.

It is a super-2 number, since 2×161621543580² (a number of 23 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 6193645 + ... + 6219684.

It is an arithmetic number, because the mean of its divisors is an integer number (5561171840).

Almost surely, 2^161621543580 is an apocalyptic number.

161621543580 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

161621543580 is an abundant number, since it is smaller than the sum of its proper divisors (372250953060).

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

161621543580 is a wasteful number, since it uses less digits than its factorization.

161621543580 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12413379 (or 12413377 counting only the distinct ones).

The product of its (nonzero) digits is 172800, while the sum is 42.

The spelling of 161621543580 in words is "one hundred sixty-one billion, six hundred twenty-one million, five hundred forty-three thousand, five hundred eighty".