648979931 has 4 divisors (see below), whose sum is σ = 655045272. Its totient is φ = 642914592.

The previous prime is 648979927. The next prime is 648979943. The reversal of 648979931 is 139979846.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 139979846 = 2 ⋅69989923.

It is a cyclic number.

It is not a de Polignac number, because 648979931 - 2² = 648979927 is a prime.

It is a super-2 number, since 2×648979931² = 842349901681529522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (648979921) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3032510 + ... + 3032723.

It is an arithmetic number, because the mean of its divisors is an integer number (163761318).

Almost surely, 2^648979931 is an apocalyptic number.

648979931 is a deficient number, since it is larger than the sum of its proper divisors (6065341).

648979931 is a wasteful number, since it uses less digits than its factorization.

648979931 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6065340.

The product of its digits is 2939328, while the sum is 56.

The square root of 648979931 is about 25475.0845140894. The cubic root of 648979931 is about 865.7857277533.

The spelling of 648979931 in words is "six hundred forty-eight million, nine hundred seventy-nine thousand, nine hundred thirty-one".