640038672 has 360 divisors, whose sum is σ = 2323420736. Its totient is φ = 166281984.

The previous prime is 640038643. The next prime is 640038673. The reversal of 640038672 is 276830046.

640038672 is a `hidden beast` number, since 640 + 0 + 3 + 8 + 6 + 7 + 2 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (640038673) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 9552783 + ... + 9552849.

Almost surely, 2^640038672 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 640038672, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1161710368).

640038672 is an abundant number, since it is smaller than the sum of its proper divisors (1683382064).

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

640038672 is an equidigital number, since it uses as much as digits as its factorization.

640038672 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 119 (or 92 counting only the distinct ones).

The product of its (nonzero) digits is 48384, while the sum is 36.

The square root of 640038672 is about 25298.9855923118. The cubic root of 640038672 is about 861.7912332253.

The spelling of 640038672 in words is "six hundred forty million, thirty-eight thousand, six hundred seventy-two".