640473813 has 12 divisors (see below), whose sum is σ = 1057290208. Its totient is φ = 365985000.

The previous prime is 640473791. The next prime is 640473871. The reversal of 640473813 is 318374046.

640473813 is a `hidden beast` number, since 640 + 4 + 7 + 3 + 8 + 1 + 3 = 666.

It is not a de Polignac number, because 640473813 - 2¹² = 640469717 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640473313) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 5083063 + ... + 5083188.

Almost surely, 2^640473813 is an apocalyptic number.

640473813 is a gapful number since it is divisible by the number (63) formed by its first and last digit.

It is an amenable number.

640473813 is a deficient number, since it is larger than the sum of its proper divisors (416816395).

640473813 is a wasteful number, since it uses less digits than its factorization.

640473813 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10166264 (or 10166261 counting only the distinct ones).

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

The square root of 640473813 is about 25307.5841004233. The cubic root of 640473813 is about 861.9864900455.

The spelling of 640473813 in words is "six hundred forty million, four hundred seventy-three thousand, eight hundred thirteen".