640777123 has 8 divisors (see below), whose sum is σ = 744322400. Its totient is φ = 540233280.

The previous prime is 640777117. The next prime is 640777139. The reversal of 640777123 is 321777046.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-640777123 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (640777153) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 749898 + ... + 750751.

It is an arithmetic number, because the mean of its divisors is an integer number (93040300).

Almost surely, 2^640777123 is an apocalyptic number.

640777123 is a deficient number, since it is larger than the sum of its proper divisors (103545277).

640777123 is a wasteful number, since it uses less digits than its factorization.

640777123 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1500717.

The product of its (nonzero) digits is 49392, while the sum is 37.

The square root of 640777123 is about 25313.5758635559. The cubic root of 640777123 is about 862.1225392517.

The spelling of 640777123 in words is "six hundred forty million, seven hundred seventy-seven thousand, one hundred twenty-three".