21825765 has 24 divisors (see below), whose sum is σ = 40742520. Its totient is φ = 10744704.

The previous prime is 21825757. The next prime is 21825887. The reversal of 21825765 is 56752812.

It is a happy number.

21825765 is a `hidden beast` number, since 2 + 1 + 82 + 576 + 5 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 314721 + 21511044 = 561^2 + 4638^2 .

It is not a de Polignac number, because 21825765 - 2³ = 21825757 is a prime.

It is a congruent number.

It is an unprimeable number.

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 23 ways as a sum of consecutive naturals, for example, 18070 + ... + 19239.

It is an arithmetic number, because the mean of its divisors is an integer number (1697605).

Almost surely, 2^21825765 is an apocalyptic number.

It is an amenable number.

21825765 is a deficient number, since it is larger than the sum of its proper divisors (18916755).

21825765 is a wasteful number, since it uses less digits than its factorization.

21825765 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37333 (or 37330 counting only the distinct ones).

The product of its digits is 33600, while the sum is 36.

The square root of 21825765 is about 4671.8053255674. The cubic root of 21825765 is about 279.4622544749.

The spelling of 21825765 in words is "twenty-one million, eight hundred twenty-five thousand, seven hundred sixty-five".