25535721 has 4 divisors (see below), whose sum is σ = 34047632. Its totient is φ = 17023812.

The previous prime is 25535693. The next prime is 25535767. The reversal of 25535721 is 12753552.

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 not a de Polignac number, because 25535721 - 2¹³ = 25527529 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (25535021) 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, 4255951 + ... + 4255956.

It is an arithmetic number, because the mean of its divisors is an integer number (8511908).

Almost surely, 2^25535721 is an apocalyptic number.

It is an amenable number.

25535721 is a deficient number, since it is larger than the sum of its proper divisors (8511911).

25535721 is an equidigital number, since it uses as much as digits as its factorization.

25535721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8511910.

The product of its digits is 10500, while the sum is 30.

The square root of 25535721 is about 5053.2881374408. The cubic root of 25535721 is about 294.4756403744.

The spelling of 25535721 in words is "twenty-five million, five hundred thirty-five thousand, seven hundred twenty-one".