21931225 has 12 divisors (see below), whose sum is σ = 28626640. Its totient is φ = 16621200.

The previous prime is 21931223. The next prime is 21931237. The reversal of 21931225 is 52213912.

It is a happy number.

It is not a de Polignac number, because 21931225 - 2¹ = 21931223 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (25).

It is a self number, because there is not a number n which added to its sum of digits gives 21931225.

It is not an unprimeable number, because it can be changed into a prime (21931223) 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 11 ways as a sum of consecutive naturals, for example, 22611 + ... + 23560.

Almost surely, 2^21931225 is an apocalyptic number.

21931225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21931225 is a deficient number, since it is larger than the sum of its proper divisors (6695415).

21931225 is a wasteful number, since it uses less digits than its factorization.

21931225 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 46200 (or 46195 counting only the distinct ones).

The product of its digits is 1080, while the sum is 25.

The square root of 21931225 is about 4683.0785814462. The cubic root of 21931225 is about 279.9116430393.

The spelling of 21931225 in words is "twenty-one million, nine hundred thirty-one thousand, two hundred twenty-five".