646404425 has 6 divisors (see below), whose sum is σ = 801541518. Its totient is φ = 517123520.

The previous prime is 646404391. The next prime is 646404427. The reversal of 646404425 is 524404646.

It can be written as a sum of positive squares in 3 ways, for example, as 24649 + 646379776 = 157^2 + 25424^2 .

It is not a de Polignac number, because 646404425 - 2⁸ = 646404169 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (646404427) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 12928064 + ... + 12928113.

It is an arithmetic number, because the mean of its divisors is an integer number (133590253).

Almost surely, 2^646404425 is an apocalyptic number.

It is an amenable number.

646404425 is a deficient number, since it is larger than the sum of its proper divisors (155137093).

646404425 is a wasteful number, since it uses less digits than its factorization.

646404425 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25856187 (or 25856182 counting only the distinct ones).

The product of its (nonzero) digits is 92160, while the sum is 35.

The square root of 646404425 is about 25424.4847538746. The cubic root of 646404425 is about 864.6389061616.

The spelling of 646404425 in words is "six hundred forty-six million, four hundred four thousand, four hundred twenty-five".