642561618600 has 864 divisors, whose sum is σ = 2483117320320. Its totient is φ = 148642560000.

The previous prime is 642561618541. The next prime is 642561618613. The reversal of 642561618600 is 6816165246.

642561618600 is a `hidden beast` number, since 6 + 4 + 2 + 561 + 6 + 1 + 86 + 0 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 215 ways as a sum of consecutive naturals, for example, 419699835 + ... + 419701365.

It is an arithmetic number, because the mean of its divisors is an integer number (2873978380).

Almost surely, 2^642561618600 is an apocalyptic number.

642561618600 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 642561618600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1241558660160).

642561618600 is an abundant number, since it is smaller than the sum of its proper divisors (1840555701720).

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

642561618600 is a wasteful number, since it uses less digits than its factorization.

642561618600 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1663 (or 1640 counting only the distinct ones).

The product of its (nonzero) digits is 414720, while the sum is 45.

The spelling of 642561618600 in words is "six hundred forty-two billion, five hundred sixty-one million, six hundred eighteen thousand, six hundred".