646220725 has 24 divisors (see below), whose sum is σ = 831239208. Its totient is φ = 497952000.

The previous prime is 646220623. The next prime is 646220737. The reversal of 646220725 is 527022646.

It can be written as a sum of positive squares in 12 ways, for example, as 2380849 + 643839876 = 1543^2 + 25374^2 .

It is not a de Polignac number, because 646220725 - 2¹³ = 646212533 is a prime.

It is a Duffinian number.

It is a congruent number.

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, 89967 + ... + 96883.

It is an arithmetic number, because the mean of its divisors is an integer number (34634967).

Almost surely, 2^646220725 is an apocalyptic number.

It is an amenable number.

646220725 is a deficient number, since it is larger than the sum of its proper divisors (185018483).

646220725 is a wasteful number, since it uses less digits than its factorization.

646220725 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7065 (or 7060 counting only the distinct ones).

The product of its (nonzero) digits is 40320, while the sum is 34.

The square root of 646220725 is about 25420.8718379209. The cubic root of 646220725 is about 864.5569919040.

The spelling of 646220725 in words is "six hundred forty-six million, two hundred twenty thousand, seven hundred twenty-five".