25721965 has 16 divisors (see below), whose sum is σ = 31804416. Its totient is φ = 19958400.

The previous prime is 25721963. The next prime is 25721977. The reversal of 25721965 is 56912752.

It is not a de Polignac number, because 25721965 - 2¹ = 25721963 is a prime.

It is a super-2 number, since 2×25721965² = 1323238966922450, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25721963) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 55324 + ... + 55786.

It is an arithmetic number, because the mean of its divisors is an integer number (1987776).

Almost surely, 2^25721965 is an apocalyptic number.

It is an amenable number.

25721965 is a deficient number, since it is larger than the sum of its proper divisors (6082451).

25721965 is a wasteful number, since it uses less digits than its factorization.

25721965 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 780.

The product of its digits is 37800, while the sum is 37.

The square root of 25721965 is about 5071.6826596308. The cubic root of 25721965 is about 295.1898232465.

It can be divided in two parts, 257 and 21965, that added together give a palindrome (22222).

The spelling of 25721965 in words is "twenty-five million, seven hundred twenty-one thousand, nine hundred sixty-five".