25776721 has 4 divisors (see below), whose sum is σ = 26897472. Its totient is φ = 24655972.

The previous prime is 25776703. The next prime is 25776733. The reversal of 25776721 is 12767752.

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 not a de Polignac number, because 25776721 - 2⁵ = 25776689 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (25776701) 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, 560341 + ... + 560386.

It is an arithmetic number, because the mean of its divisors is an integer number (6724368).

Almost surely, 2^25776721 is an apocalyptic number.

It is an amenable number.

25776721 is a deficient number, since it is larger than the sum of its proper divisors (1120751).

25776721 is a wasteful number, since it uses less digits than its factorization.

25776721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1120750.

The product of its digits is 41160, while the sum is 37.

The square root of 25776721 is about 5077.0779982191. The cubic root of 25776721 is about 295.3991379721.

The spelling of 25776721 in words is "twenty-five million, seven hundred seventy-six thousand, seven hundred twenty-one".