25391921 has 8 divisors (see below), whose sum is σ = 25951464. Its totient is φ = 24837120.

The previous prime is 25391909. The next prime is 25391963. The reversal of 25391921 is 12919352.

It can be written as a sum of positive squares in 4 ways, for example, as 30625 + 25361296 = 175^2 + 5036^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-25391921 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (25391021) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10961 + ... + 13073.

It is an arithmetic number, because the mean of its divisors is an integer number (3243933).

Almost surely, 2^25391921 is an apocalyptic number.

It is an amenable number.

25391921 is a deficient number, since it is larger than the sum of its proper divisors (559543).

25391921 is a wasteful number, since it uses less digits than its factorization.

25391921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2371.

The product of its digits is 4860, while the sum is 32.

The square root of 25391921 is about 5039.0396902585. The cubic root of 25391921 is about 293.9218366263.

The spelling of 25391921 in words is "twenty-five million, three hundred ninety-one thousand, nine hundred twenty-one".