21353725 has 6 divisors (see below), whose sum is σ = 26478650. Its totient is φ = 17082960.

The previous prime is 21353711. The next prime is 21353737. The reversal of 21353725 is 52735312.

It can be written as a sum of positive squares in 3 ways, for example, as 395641 + 20958084 = 629^2 + 4578^2 .

It is not a de Polignac number, because 21353725 - 2¹⁷ = 21222653 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21353693 and 21353702.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 427050 + ... + 427099.

Almost surely, 2^21353725 is an apocalyptic number.

21353725 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21353725 is a deficient number, since it is larger than the sum of its proper divisors (5124925).

21353725 is an equidigital number, since it uses as much as digits as its factorization.

21353725 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 854159 (or 854154 counting only the distinct ones).

The product of its digits is 6300, while the sum is 28.

The square root of 21353725 is about 4621.0090889328. The cubic root of 21353725 is about 277.4328490495.

The spelling of 21353725 in words is "twenty-one million, three hundred fifty-three thousand, seven hundred twenty-five".