640110402 has 12 divisors (see below), whose sum is σ = 1386905910. Its totient is φ = 213370128.

The previous prime is 640110391. The next prime is 640110431. The reversal of 640110402 is 204011046.

It can be written as a sum of positive squares in only one way, i.e., 412130601 + 227979801 = 20301^2 + 15099^2 .

It is a Harshad number since it is a multiple of its sum of digits (18), and also a Moran number because the ratio is a prime number: 35561689 = 640110402 / (6 + 4 + 0 + 1 + 1 + 0 + 4 + 0 + 2).

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 17780827 + ... + 17780862.

Almost surely, 2^640110402 is an apocalyptic number.

640110402 is an abundant number, since it is smaller than the sum of its proper divisors (746795508).

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

640110402 is a wasteful number, since it uses less digits than its factorization.

640110402 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 35561697 (or 35561694 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

The square root of 640110402 is about 25300.4031983682. The cubic root of 640110402 is about 861.8234260592.

Adding to 640110402 its reverse (204011046), we get a palindrome (844121448).

The spelling of 640110402 in words is "six hundred forty million, one hundred ten thousand, four hundred two".