642738776064 has 768 divisors, whose sum is σ = 2228594135040. Its totient is φ = 159889489920.

The previous prime is 642738776063. The next prime is 642738776077. The reversal of 642738776064 is 460677837246.

It is a tau number, because it is divible by the number of its divisors (768).

It is a super-2 number, since 2×642738776064² (a number of 24 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 642738775989 and 642738776007.

It is not an unprimeable number, because it can be changed into a prime (642738776063) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 1277810437 + ... + 1277810939.

It is an arithmetic number, because the mean of its divisors is an integer number (2901815280).

Almost surely, 2^642738776064 is an apocalyptic number.

642738776064 is a gapful number since it is divisible by the number (64) 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 642738776064, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1114297067520).

642738776064 is an abundant number, since it is smaller than the sum of its proper divisors (1585855358976).

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

642738776064 is a wasteful number, since it uses less digits than its factorization.

642738776064 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 656 (or 636 counting only the distinct ones).

The product of its (nonzero) digits is 56899584, while the sum is 60.

The spelling of 642738776064 in words is "six hundred forty-two billion, seven hundred thirty-eight million, seven hundred seventy-six thousand, sixty-four".