25664421 has 32 divisors (see below), whose sum is σ = 37987840. Its totient is φ = 15349824.

The previous prime is 25664371. The next prime is 25664423. The reversal of 25664421 is 12446652.

It is not a de Polignac number, because 25664421 - 2¹⁰ = 25663397 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25664423) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 90546 + ... + 90828.

It is an arithmetic number, because the mean of its divisors is an integer number (1187120).

Almost surely, 2^25664421 is an apocalyptic number.

It is an amenable number.

25664421 is a deficient number, since it is larger than the sum of its proper divisors (12323419).

25664421 is a wasteful number, since it uses less digits than its factorization.

25664421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 385.

The product of its digits is 11520, while the sum is 30.

The square root of 25664421 is about 5066.0064153137. The cubic root of 25664421 is about 294.9695305119.

The spelling of 25664421 in words is "twenty-five million, six hundred sixty-four thousand, four hundred twenty-one".