645554554920 has 160 divisors (see below), whose sum is σ = 2367033498720. Its totient is φ = 156498065280.

The previous prime is 645554554919. The next prime is 645554554949. The reversal of 645554554920 is 29455455546.

645554554920 is a `hidden beast` number, since 6 + 4 + 5 + 5 + 545 + 5 + 4 + 92 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 9020962 + ... + 9092241.

It is an arithmetic number, because the mean of its divisors is an integer number (14793959367).

Almost surely, 2^645554554920 is an apocalyptic number.

645554554920 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

645554554920 is an abundant number, since it is smaller than the sum of its proper divisors (1721478943800).

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

645554554920 is a wasteful number, since it uses less digits than its factorization.

645554554920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18113237 (or 18113224 counting only the distinct ones).

The product of its (nonzero) digits is 21600000, while the sum is 54.

The spelling of 645554554920 in words is "six hundred forty-five billion, five hundred fifty-four million, five hundred fifty-four thousand, nine hundred twenty".