21951225 has 18 divisors (see below), whose sum is σ = 39317486. Its totient is φ = 11707200.

The previous prime is 21951221. The next prime is 21951229. The reversal of 21951225 is 52215912.

It is an interprime number because it is at equal distance from previous prime (21951221) and next prime (21951229).

It can be written as a sum of positive squares in 3 ways, for example, as 20736 + 21930489 = 144^2 + 4683^2 .

It is not a de Polignac number, because 21951225 - 2² = 21951221 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21951221) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 48556 + ... + 49005.

Almost surely, 2^21951225 is an apocalyptic number.

21951225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21951225 is a deficient number, since it is larger than the sum of its proper divisors (17366261).

21951225 is a wasteful number, since it uses less digits than its factorization.

21951225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 97577 (or 97569 counting only the distinct ones).

The product of its digits is 1800, while the sum is 27.

The square root of 21951225 is about 4685.2134423098. The cubic root of 21951225 is about 279.9967048932.

The spelling of 21951225 in words is "twenty-one million, nine hundred fifty-one thousand, two hundred twenty-five".