6420015625 has 21 divisors (see below), whose sum is σ = 8037455713. Its totient is φ = 5128000000.

The previous prime is 6420015617. The next prime is 6420015631. The reversal of 6420015625 is 5265100246.

The square root of 6420015625 is 80125.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 10 ways, for example, as 6408482809 + 11532816 = 80053^2 + 3396^2 .

It is not a de Polignac number, because 6420015625 - 2³ = 6420015617 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 20 ways as a sum of consecutive naturals, for example, 10015305 + ... + 10015945.

Almost surely, 2^6420015625 is an apocalyptic number.

6420015625 is the 80125-th square number.

6420015625 is the 40063-rd centered octagonal number.

It is an amenable number.

6420015625 is a deficient number, since it is larger than the sum of its proper divisors (1617440088).

6420015625 is an frugal number, since it uses more digits than its factorization.

6420015625 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1312 (or 646 counting only the distinct ones).

The product of its (nonzero) digits is 14400, while the sum is 31.

The cubic root of 6420015625 is about 1858.5690254973.

Multiplying 6420015625 by its product of nonzero digits (14400), we get a square (92448225000000 = 9615000²).

The spelling of 6420015625 in words is "six billion, four hundred twenty million, fifteen thousand, six hundred twenty-five".