25428921 has 16 divisors (see below), whose sum is σ = 38922624. Its totient is φ = 14465664.

The previous prime is 25428917. The next prime is 25428929. The reversal of 25428921 is 12982452.

It is not a de Polignac number, because 25428921 - 2² = 25428917 is a prime.

It is not an unprimeable number, because it can be changed into a prime (25428929) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2295 + ... + 7491.

It is an arithmetic number, because the mean of its divisors is an integer number (2432664).

Almost surely, 2^25428921 is an apocalyptic number.

25428921 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

25428921 is a deficient number, since it is larger than the sum of its proper divisors (13493703).

25428921 is a wasteful number, since it uses less digits than its factorization.

25428921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5440.

The product of its digits is 11520, while the sum is 33.

The square root of 25428921 is about 5042.7096882529. The cubic root of 25428921 is about 294.0645307005.

The spelling of 25428921 in words is "twenty-five million, four hundred twenty-eight thousand, nine hundred twenty-one".