646978835 has 24 divisors (see below), whose sum is σ = 830068560. Its totient is φ = 483510720.

The previous prime is 646978819. The next prime is 646978859. The reversal of 646978835 is 538879646.

It is not a de Polignac number, because 646978835 - 2⁴ = 646978819 is a prime.

It is a super-2 number, since 2×646978835² = 837163225875914450, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 137024 + ... + 141666.

It is an arithmetic number, because the mean of its divisors is an integer number (34586190).

Almost surely, 2^646978835 is an apocalyptic number.

646978835 is a deficient number, since it is larger than the sum of its proper divisors (183089725).

646978835 is a wasteful number, since it uses less digits than its factorization.

646978835 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4739 (or 4708 counting only the distinct ones).

The product of its digits is 8709120, while the sum is 56.

The square root of 646978835 is about 25435.7786395463. The cubic root of 646978835 is about 864.8949430810.

The spelling of 646978835 in words is "six hundred forty-six million, nine hundred seventy-eight thousand, eight hundred thirty-five".