25309309921 has 9 divisors (see below), whose sum is σ = 29442737649. Its totient is φ = 21692739684.

The previous prime is 25309309919. The next prime is 25309309957. The reversal of 25309309921 is 12990390352.

The square root of 25309309921 is 159089.

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

It is not a de Polignac number, because 25309309921 - 2¹ = 25309309919 is a prime.

It is a super-2 number, since 2×25309309921² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (25309309901) by changing a digit.

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, 1102260 + ... + 1124986.

Almost surely, 2^25309309921 is an apocalyptic number.

25309309921 is the 159089-th square number.

25309309921 is the 79545-th centered octagonal number.

It is an amenable number.

25309309921 is a deficient number, since it is larger than the sum of its proper divisors (4133427728).

25309309921 is an frugal number, since it uses more digits than its factorization.

25309309921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 45468 (or 22734 counting only the distinct ones).

The product of its (nonzero) digits is 131220, while the sum is 43.

The spelling of 25309309921 in words is "twenty-five billion, three hundred nine million, three hundred nine thousand, nine hundred twenty-one".