640220672 has 180 divisors, whose sum is σ = 1621978776. Its totient is φ = 251596800.

The previous prime is 640220653. The next prime is 640220677. The reversal of 640220672 is 276022046.

It is a super-2 number, since 2×640220672² = 819765017712263168, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640220677) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 4239797 + ... + 4239947.

Almost surely, 2^640220672 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 640220672, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (810989388).

640220672 is an abundant number, since it is smaller than the sum of its proper divisors (981758104).

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

640220672 is a wasteful number, since it uses less digits than its factorization.

640220672 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 209 (or 173 counting only the distinct ones).

The product of its (nonzero) digits is 8064, while the sum is 29.

The square root of 640220672 is about 25302.5823188069. The cubic root of 640220672 is about 861.8729111753.

The spelling of 640220672 in words is "six hundred forty million, two hundred twenty thousand, six hundred seventy-two".