645591983986 has 16 divisors (see below), whose sum is σ = 1025403515136. Its totient is φ = 303792721216.

The previous prime is 645591983983. The next prime is 645591984007. The reversal of 645591983986 is 689389195546.

645591983986 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not an unprimeable number, because it can be changed into a prime (645591983983) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 224055 + ... + 1158181.

It is an arithmetic number, because the mean of its divisors is an integer number (64087719696).

Almost surely, 2^645591983986 is an apocalyptic number.

645591983986 is a deficient number, since it is larger than the sum of its proper divisors (379811531150).

645591983986 is a wasteful number, since it uses less digits than its factorization.

645591983986 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 954473.

The product of its digits is 503884800, while the sum is 73.

The spelling of 645591983986 in words is "six hundred forty-five billion, five hundred ninety-one million, nine hundred eighty-three thousand, nine hundred eighty-six".