640304637106 has 4 divisors (see below), whose sum is σ = 960456955662. Its totient is φ = 320152318552.

The previous prime is 640304637103. The next prime is 640304637113. The reversal of 640304637106 is 601736403046.

It is a happy number.

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., 421973664025 + 218330973081 = 649595^2 + 467259^2 .

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (640304637103) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 160076159275 + ... + 160076159278.

Almost surely, 2^640304637106 is an apocalyptic number.

640304637106 is a deficient number, since it is larger than the sum of its proper divisors (320152318556).

640304637106 is a wasteful number, since it uses less digits than its factorization.

640304637106 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 320152318555.

The product of its (nonzero) digits is 217728, while the sum is 40.

The spelling of 640304637106 in words is "six hundred forty billion, three hundred four million, six hundred thirty-seven thousand, one hundred six".