9991002025 has 9 divisors (see below), whose sum is σ = 12389462263. Its totient is φ = 7992401800.

The previous prime is 9991002013. The next prime is 9991002089. The reversal of 9991002025 is 5202001999.

The square root of 9991002025 is 99955.

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., 3596760729 + 6394241296 = 59973^2 + 79964^2 .

It is not a de Polignac number, because 9991002025 - 2²¹ = 9988904873 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 489780 + ... + 509770.

Almost surely, 2^9991002025 is an apocalyptic number.

9991002025 is the 99955-th square number.

9991002025 is the 49978-th centered octagonal number.

It is an amenable number.

9991002025 is a deficient number, since it is larger than the sum of its proper divisors (2398460238).

9991002025 is an frugal number, since it uses more digits than its factorization.

9991002025 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39992 (or 19996 counting only the distinct ones).

The product of its (nonzero) digits is 14580, while the sum is 37.

The cubic root of 9991002025 is about 2153.7883111404.

The spelling of 9991002025 in words is "nine billion, nine hundred ninety-one million, two thousand, twenty-five".