25478021 has 4 divisors (see below), whose sum is σ = 25630752. Its totient is φ = 25325292.

The previous prime is 25478009. The next prime is 25478051. The reversal of 25478021 is 12087452.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-25478021 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25478051) 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, 76115 + ... + 76448.

It is an arithmetic number, because the mean of its divisors is an integer number (6407688).

Almost surely, 2^25478021 is an apocalyptic number.

It is an amenable number.

25478021 is a deficient number, since it is larger than the sum of its proper divisors (152731).

25478021 is a wasteful number, since it uses less digits than its factorization.

25478021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 152730.

The product of its (nonzero) digits is 4480, while the sum is 29.

The square root of 25478021 is about 5047.5757547559. The cubic root of 25478021 is about 294.2536760363.

The spelling of 25478021 in words is "twenty-five million, four hundred seventy-eight thousand, twenty-one".