640898016 has 192 divisors, whose sum is σ = 1930521600. Its totient is φ = 184412160.

The previous prime is 640897997. The next prime is 640898047. The reversal of 640898016 is 610898046.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1836210 + ... + 1836558.

It is an arithmetic number, because the mean of its divisors is an integer number (10054800).

Almost surely, 2^640898016 is an apocalyptic number.

640898016 is a gapful number since it is divisible by the number (66) 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 640898016, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (965260800).

640898016 is an abundant number, since it is smaller than the sum of its proper divisors (1289623584).

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

640898016 is a wasteful number, since it uses less digits than its factorization.

640898016 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 457 (or 449 counting only the distinct ones).

The product of its (nonzero) digits is 82944, while the sum is 42.

The square root of 640898016 is about 25315.9636593198. The cubic root of 640898016 is about 862.1767536436.

The spelling of 640898016 in words is "six hundred forty million, eight hundred ninety-eight thousand, sixteen".