25121299009 has 9 divisors (see below), whose sum is σ = 25248899113. Its totient is φ = 24994342912.

The previous prime is 25121299001. The next prime is 25121299019. The reversal of 25121299009 is 90099212152.

The square root of 25121299009 is 158497.

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

It can be written as a sum of positive squares in 4 ways, for example, as 7924225 + 25113374784 = 2815^2 + 158472^2 .

It is not a de Polignac number, because 25121299009 - 2³ = 25121299001 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (25121299001) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 55949217 + ... + 55949665.

Almost surely, 2^25121299009 is an apocalyptic number.

25121299009 is the 158497-th square number.

25121299009 is the 79249-th centered octagonal number.

It is an amenable number.

25121299009 is a deficient number, since it is larger than the sum of its proper divisors (127600104).

25121299009 is an frugal number, since it uses more digits than its factorization.

25121299009 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1604 (or 802 counting only the distinct ones).

The product of its (nonzero) digits is 29160, while the sum is 40.

The spelling of 25121299009 in words is "twenty-five billion, one hundred twenty-one million, two hundred ninety-nine thousand, nine".