2161637664 has 48 divisors (see below), whose sum is σ = 5677056000. Its totient is φ = 720195840.

The previous prime is 2161637609. The next prime is 2161637713. The reversal of 2161637664 is 4667361612.

It is a tau number, because it is divible by the number of its divisors (48).

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 259809 + ... + 267999.

It is an arithmetic number, because the mean of its divisors is an integer number (118272000).

Almost surely, 2^2161637664 is an apocalyptic number.

2161637664 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

2161637664 is an abundant number, since it is smaller than the sum of its proper divisors (3515418336).

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

2161637664 is a wasteful number, since it uses less digits than its factorization.

2161637664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10953 (or 10945 counting only the distinct ones).

The product of its digits is 217728, while the sum is 42.

The square root of 2161637664 is about 46493.4152757140. The cubic root of 2161637664 is about 1292.9874203923.

The spelling of 2161637664 in words is "two billion, one hundred sixty-one million, six hundred thirty-seven thousand, six hundred sixty-four".