642521216 has 64 divisors (see below), whose sum is σ = 1332936000. Its totient is φ = 308130816.

The previous prime is 642521207. The next prime is 642521237. The reversal of 642521216 is 612125246.

It is a tau number, because it is divible by the number of its divisors (64).

It is a Harshad number since it is a multiple of its sum of digits (29).

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, 663965 + ... + 664931.

It is an arithmetic number, because the mean of its divisors is an integer number (20827125).

Almost surely, 2^642521216 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 642521216, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (666468000).

642521216 is an abundant number, since it is smaller than the sum of its proper divisors (690414784).

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

642521216 is a wasteful number, since it uses less digits than its factorization.

642521216 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1189 (or 1177 counting only the distinct ones).

The product of its digits is 5760, while the sum is 29.

The square root of 642521216 is about 25348.0022092472. The cubic root of 642521216 is about 862.9040172856.

The spelling of 642521216 in words is "six hundred forty-two million, five hundred twenty-one thousand, two hundred sixteen".