646245128 has 8 divisors (see below), whose sum is σ = 1211709630. Its totient is φ = 323122560.

The previous prime is 646245101. The next prime is 646245143. The reversal of 646245128 is 821542646.

It can be written as a sum of positive squares in only one way, i.e., 633126244 + 13118884 = 25162^2 + 3622^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is a junction number, because it is equal to n+sod(n) for n = 646245091 and 646245100.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40390313 + ... + 40390328.

Almost surely, 2^646245128 is an apocalyptic number.

It is an amenable number.

646245128 is a deficient number, since it is larger than the sum of its proper divisors (565464502).

646245128 is a wasteful number, since it uses less digits than its factorization.

646245128 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 80780647 (or 80780643 counting only the distinct ones).

The product of its digits is 92160, while the sum is 38.

The square root of 646245128 is about 25421.3518129937. The cubic root of 646245128 is about 864.5678744183.

The spelling of 646245128 in words is "six hundred forty-six million, two hundred forty-five thousand, one hundred twenty-eight".