25981221 has 20 divisors (see below), whose sum is σ = 40424032. Its totient is φ = 14842296.

The previous prime is 25981217. The next prime is 25981297. The reversal of 25981221 is 12218952.

It is not a de Polignac number, because 25981221 - 2² = 25981217 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 (25981201) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 5400 + ... + 9006.

Almost surely, 2^25981221 is an apocalyptic number.

25981221 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

25981221 is a deficient number, since it is larger than the sum of its proper divisors (14442811).

25981221 is an frugal number, since it uses more digits than its factorization.

25981221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3638 (or 3617 counting only the distinct ones).

The product of its digits is 2880, while the sum is 30.

The square root of 25981221 is about 5097.1777485193. The cubic root of 25981221 is about 296.1782656703.

The spelling of 25981221 in words is "twenty-five million, nine hundred eighty-one thousand, two hundred twenty-one".