642220817820 has 24 divisors (see below), whose sum is σ = 1798218290064. Its totient is φ = 171258884736.

The previous prime is 642220817807. The next prime is 642220817857. The reversal of 642220817820 is 28718022246.

It is a congruent number.

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, 5351840089 + ... + 5351840208.

It is an arithmetic number, because the mean of its divisors is an integer number (74925762086).

Almost surely, 2^642220817820 is an apocalyptic number.

642220817820 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

642220817820 is an abundant number, since it is smaller than the sum of its proper divisors (1155997472244).

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

642220817820 is a wasteful number, since it uses less digits than its factorization.

642220817820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10703680309 (or 10703680307 counting only the distinct ones).

The product of its (nonzero) digits is 172032, while the sum is 42.

The spelling of 642220817820 in words is "six hundred forty-two billion, two hundred twenty million, eight hundred seventeen thousand, eight hundred twenty".