1981965720 has 96 divisors (see below), whose sum is σ = 6916676400. Its totient is φ = 453019392.

The previous prime is 1981965709. The next prime is 1981965721. The reversal of 1981965720 is 275691891.

It is a self number, because there is not a number n which added to its sum of digits gives 1981965720.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1981965721) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 162655 + ... + 174414.

Almost surely, 2^1981965720 is an apocalyptic number.

1981965720 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1981965720 is an abundant number, since it is smaller than the sum of its proper divisors (4934710680).

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

1981965720 is a wasteful number, since it uses less digits than its factorization.

1981965720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 337097 (or 337086 counting only the distinct ones).

The product of its (nonzero) digits is 272160, while the sum is 48.

The square root of 1981965720 is about 44519.2735789793. The cubic root of 1981965720 is about 1256.1226485095.

The spelling of 1981965720 in words is "one billion, nine hundred eighty-one million, nine hundred sixty-five thousand, seven hundred twenty".