642555816 has 48 divisors (see below), whose sum is σ = 1868660640. Its totient is φ = 183587040.

The previous prime is 642555811. The next prime is 642555821. The reversal of 642555816 is 618555246.

642555816 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (642555811) and next prime (642555821).

It is a super-3 number, since 3×642555816³ (a number of 27 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is not an unprimeable number, because it can be changed into a prime (642555811) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 272020 + ... + 274371.

It is an arithmetic number, because the mean of its divisors is an integer number (38930430).

Almost surely, 2^642555816 is an apocalyptic number.

It is an amenable number.

642555816 is an abundant number, since it is smaller than the sum of its proper divisors (1226104824).

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

642555816 is a wasteful number, since it uses less digits than its factorization.

642555816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 546414 (or 546403 counting only the distinct ones).

The product of its digits is 288000, while the sum is 42.

The square root of 642555816 is about 25348.6846996052. The cubic root of 642555816 is about 862.9195062387.

The spelling of 642555816 in words is "six hundred forty-two million, five hundred fifty-five thousand, eight hundred sixteen".