25013078921 has 4 divisors (see below), whose sum is σ = 25270945812. Its totient is φ = 24755212032.

The previous prime is 25013078891. The next prime is 25013078939. The reversal of 25013078921 is 12987031052.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 10208273296 + 14804805625 = 101036^2 + 121675^2 .

It is a cyclic number.

It is not a de Polignac number, because 25013078921 - 2¹⁰ = 25013077897 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (25013078971) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 128933300 + ... + 128933493.

It is an arithmetic number, because the mean of its divisors is an integer number (6317736453).

Almost surely, 2^25013078921 is an apocalyptic number.

It is an amenable number.

25013078921 is a deficient number, since it is larger than the sum of its proper divisors (257866891).

25013078921 is an equidigital number, since it uses as much as digits as its factorization.

25013078921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 257866890.

The product of its (nonzero) digits is 30240, while the sum is 38.

The spelling of 25013078921 in words is "twenty-five billion, thirteen million, seventy-eight thousand, nine hundred twenty-one".