648704857 has 16 divisors (see below), whose sum is σ = 715184640. Its totient is φ = 586328512.

The previous prime is 648704839. The next prime is 648704869. The reversal of 648704857 is 758407846.

It is a happy number.

It is a de Polignac number, because none of the positive numbers 2^k-648704857 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 648704857.

It is not an unprimeable number, because it can be changed into a prime (648704807) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 21003 + ... + 41695.

It is an arithmetic number, because the mean of its divisors is an integer number (44699040).

Almost surely, 2^648704857 is an apocalyptic number.

It is an amenable number.

648704857 is a deficient number, since it is larger than the sum of its proper divisors (66479783).

648704857 is a wasteful number, since it uses less digits than its factorization.

648704857 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20792.

The product of its (nonzero) digits is 1505280, while the sum is 49.

The square root of 648704857 is about 25469.6850589088. The cubic root of 648704857 is about 865.6633876584.

The spelling of 648704857 in words is "six hundred forty-eight million, seven hundred four thousand, eight hundred fifty-seven".