1981620437664 has 96 divisors (see below), whose sum is σ = 6011657688960. Its totient is φ = 559815708672.

The previous prime is 1981620437653. The next prime is 1981620437701. The reversal of 1981620437664 is 4667340261891.

It is a tau number, because it is divible by the number of its divisors (96).

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, 16506709 + ... + 16626324.

It is an arithmetic number, because the mean of its divisors is an integer number (62621434260).

Almost surely, 2^{1981620437664} is an apocalyptic number.

1981620437664 is a gapful number since it is divisible by the number (14) formed by its first and last digit.

It is an amenable number.

1981620437664 is an abundant number, since it is smaller than the sum of its proper divisors (4030037251296).

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

1981620437664 is a wasteful number, since it uses less digits than its factorization.

1981620437664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33133142 (or 33133134 counting only the distinct ones).

The product of its (nonzero) digits is 10450944, while the sum is 57.

The spelling of 1981620437664 in words is "one trillion, nine hundred eighty-one billion, six hundred twenty million, four hundred thirty-seven thousand, six hundred sixty-four".