21764025 has 48 divisors (see below), whose sum is σ = 42110400. Its totient is φ = 10990080.

The previous prime is 21764021. The next prime is 21764027. The reversal of 21764025 is 52046712.

21764025 is a `hidden beast` number, since 2 + 17 + 640 + 2 + 5 = 666.

It is not a de Polignac number, because 21764025 - 2² = 21764021 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a self number, because there is not a number n which added to its sum of digits gives 21764025.

It is not an unprimeable number, because it can be changed into a prime (21764021) 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 47 ways as a sum of consecutive naturals, for example, 11977 + ... + 13673.

It is an arithmetic number, because the mean of its divisors is an integer number (877300).

Almost surely, 2^21764025 is an apocalyptic number.

21764025 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21764025 is a deficient number, since it is larger than the sum of its proper divisors (20346375).

21764025 is a wasteful number, since it uses less digits than its factorization.

21764025 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1735 (or 1724 counting only the distinct ones).

The product of its (nonzero) digits is 3360, while the sum is 27.

The square root of 21764025 is about 4665.1929220558. The cubic root of 21764025 is about 279.1984944282.

The spelling of 21764025 in words is "twenty-one million, seven hundred sixty-four thousand, twenty-five".