642561040 has 80 divisors (see below), whose sum is σ = 1667768256. Its totient is φ = 228211200.

The previous prime is 642561011. The next prime is 642561079. The reversal of 642561040 is 40165246.

It is a tau number, because it is divible by the number of its divisors (80).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 29350 + ... + 46330.

Almost surely, 2^642561040 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 642561040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (833884128).

642561040 is an abundant number, since it is smaller than the sum of its proper divisors (1025207216).

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

642561040 is a wasteful number, since it uses less digits than its factorization.

642561040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17048 (or 17042 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 28.

The square root of 642561040 is about 25348.7877422176. The cubic root of 642561040 is about 862.9218447538.

The spelling of 642561040 in words is "six hundred forty-two million, five hundred sixty-one thousand, forty".