161631447720 has 64 divisors (see below), whose sum is σ = 490736473920. Its totient is φ = 42582418944.

The previous prime is 161631447701. The next prime is 161631447751. The reversal of 161631447720 is 27744136161.

It is a super-2 number, since 2×161631447720² (a number of 23 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8104069 + ... + 8123988.

It is an arithmetic number, because the mean of its divisors is an integer number (7667757405).

Almost surely, 2^161631447720 is an apocalyptic number.

161631447720 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

161631447720 is an abundant number, since it is smaller than the sum of its proper divisors (329105026200).

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

161631447720 is a wasteful number, since it uses less digits than its factorization.

161631447720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16228154 (or 16228150 counting only the distinct ones).

The product of its (nonzero) digits is 169344, while the sum is 42.

The spelling of 161631447720 in words is "one hundred sixty-one billion, six hundred thirty-one million, four hundred forty-seven thousand, seven hundred twenty".