999990000025 has 9 divisors (see below), whose sum is σ = 1239993800031. Its totient is φ = 799988000040.

The previous prime is 999990000017. The next prime is 999990000067. The reversal of 999990000025 is 520000099999.

The square root of 999990000025 is 999995.

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

It can be written as a sum of positive squares in only one way, i.e., 359996400009 + 639993600016 = 599997^2 + 799996^2 .

It is not a de Polignac number, because 999990000025 - 2³ = 999990000017 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 (19) of ones.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 4899976 + ... + 5099974.

Almost surely, 2^999990000025 is an apocalyptic number.

999990000025 is the 999995-th square number.

999990000025 is the 499998-th centered octagonal number.

It is an amenable number.

999990000025 is a deficient number, since it is larger than the sum of its proper divisors (240003800006).

999990000025 is an frugal number, since it uses more digits than its factorization.

999990000025 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 400008 (or 200004 counting only the distinct ones).

The product of its (nonzero) digits is 590490, while the sum is 52.

The spelling of 999990000025 in words is "nine hundred ninety-nine billion, nine hundred ninety million, twenty-five", and thus it is an aban number.