21600725 has 6 divisors (see below), whose sum is σ = 26784930. Its totient is φ = 17280560.

The previous prime is 21600673. The next prime is 21600743. The reversal of 21600725 is 52700612.

It can be written as a sum of positive squares in 3 ways, for example, as 5424241 + 16176484 = 2329^2 + 4022^2 .

It is not a de Polignac number, because 21600725 - 2¹⁰ = 21599701 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21600725.

It is a congruent number.

It is an unprimeable number.

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 5 ways as a sum of consecutive naturals, for example, 431990 + ... + 432039.

It is an arithmetic number, because the mean of its divisors is an integer number (4464155).

Almost surely, 2^21600725 is an apocalyptic number.

21600725 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21600725 is a deficient number, since it is larger than the sum of its proper divisors (5184205).

21600725 is an equidigital number, since it uses as much as digits as its factorization.

21600725 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 864039 (or 864034 counting only the distinct ones).

The product of its (nonzero) digits is 840, while the sum is 23.

The square root of 21600725 is about 4647.6580123757. The cubic root of 21600725 is about 278.4984458633.

The spelling of 21600725 in words is "twenty-one million, six hundred thousand, seven hundred twenty-five".