21764225 has 12 divisors (see below), whose sum is σ = 30843264. Its totient is φ = 14923920.

The previous prime is 21764221. The next prime is 21764227. The reversal of 21764225 is 52246712.

It is a happy number.

It is not a de Polignac number, because 21764225 - 2² = 21764221 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21764221) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 62009 + ... + 62358.

It is an arithmetic number, because the mean of its divisors is an integer number (2570272).

Almost surely, 2^21764225 is an apocalyptic number.

21764225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21764225 is a deficient number, since it is larger than the sum of its proper divisors (9079039).

21764225 is a wasteful number, since it uses less digits than its factorization.

21764225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 124384 (or 124379 counting only the distinct ones).

The product of its digits is 6720, while the sum is 29.

The square root of 21764225 is about 4665.2143573474. The cubic root of 21764225 is about 279.1993496549.

The spelling of 21764225 in words is "twenty-one million, seven hundred sixty-four thousand, two hundred twenty-five".