1981863564 has 24 divisors (see below), whose sum is σ = 4625518128. Its totient is φ = 660454080.

The previous prime is 1981863547. The next prime is 1981863577. The reversal of 1981863564 is 4653681891.

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, 34374 + ... + 71730.

It is an arithmetic number, because the mean of its divisors is an integer number (192729922).

Almost surely, 2^1981863564 is an apocalyptic number.

It is an amenable number.

1981863564 is an abundant number, since it is smaller than the sum of its proper divisors (2643654564).

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

1981863564 is a wasteful number, since it uses less digits than its factorization.

1981863564 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41785 (or 41783 counting only the distinct ones).

The product of its digits is 1244160, while the sum is 51.

The square root of 1981863564 is about 44518.1262408920. The cubic root of 1981863564 is about 1256.1010667925.

The spelling of 1981863564 in words is "one billion, nine hundred eighty-one million, eight hundred sixty-three thousand, five hundred sixty-four".