642776064 has 176 divisors, whose sum is σ = 1990273536. Its totient is φ = 180633600.

The previous prime is 642776063. The next prime is 642776077. The reversal of 642776064 is 460677246.

It is a super-2 number, since 2×642776064² = 826322136902664192, which contains 22 as substring.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (642776063) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1526574 + ... + 1526994.

Almost surely, 2^642776064 is an apocalyptic number.

642776064 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 642776064, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (995136768).

642776064 is an abundant number, since it is smaller than the sum of its proper divisors (1347497472).

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

642776064 is a wasteful number, since it uses less digits than its factorization.

642776064 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 522 (or 504 counting only the distinct ones).

The product of its (nonzero) digits is 338688, while the sum is 42.

The square root of 642776064 is about 25353.0286948128. The cubic root of 642776064 is about 863.0180888986.

The spelling of 642776064 in words is "six hundred forty-two million, seven hundred seventy-six thousand, sixty-four".