640761398 has 4 divisors (see below), whose sum is σ = 961142100. Its totient is φ = 320380698.

The previous prime is 640761397. The next prime is 640761421. The reversal of 640761398 is 893167046.

640761398 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640761397) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 160190348 + ... + 160190351.

It is an arithmetic number, because the mean of its divisors is an integer number (240285525).

Almost surely, 2^640761398 is an apocalyptic number.

640761398 is a deficient number, since it is larger than the sum of its proper divisors (320380702).

640761398 is a wasteful number, since it uses less digits than its factorization.

640761398 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 320380701.

The product of its (nonzero) digits is 217728, while the sum is 44.

The square root of 640761398 is about 25313.2652575680. The cubic root of 640761398 is about 862.1154868839.

The spelling of 640761398 in words is "six hundred forty million, seven hundred sixty-one thousand, three hundred ninety-eight".