640780202 has 4 divisors (see below), whose sum is σ = 961170306. Its totient is φ = 320390100.

The previous prime is 640780141. The next prime is 640780223. The reversal of 640780202 is 202087046.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 578354401 + 62425801 = 24049^2 + 7901^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 160195049 + ... + 160195052.

Almost surely, 2^640780202 is an apocalyptic number.

640780202 is a deficient number, since it is larger than the sum of its proper divisors (320390104).

640780202 is a wasteful number, since it uses less digits than its factorization.

640780202 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 320390103.

The product of its (nonzero) digits is 5376, while the sum is 29.

The square root of 640780202 is about 25313.6366806510. The cubic root of 640780202 is about 862.1239201119.

The spelling of 640780202 in words is "six hundred forty million, seven hundred eighty thousand, two hundred two".