21360725 has 12 divisors (see below), whose sum is σ = 26544804. Its totient is φ = 17051520.

The previous prime is 21360709. The next prime is 21360743. The reversal of 21360725 is 52706312.

It can be written as a sum of positive squares in 6 ways, for example, as 2053489 + 19307236 = 1433^2 + 4394^2 .

It is not a de Polignac number, because 21360725 - 2⁴ = 21360709 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21360694 and 21360703.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 20927 + ... + 21923.

It is an arithmetic number, because the mean of its divisors is an integer number (2212067).

Almost surely, 2^21360725 is an apocalyptic number.

21360725 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21360725 is a deficient number, since it is larger than the sum of its proper divisors (5184079).

21360725 is an equidigital number, since it uses as much as digits as its factorization.

21360725 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1864 (or 1859 counting only the distinct ones).

The product of its (nonzero) digits is 2520, while the sum is 26.

The square root of 21360725 is about 4621.7664371969. The cubic root of 21360725 is about 277.4631609783.

The spelling of 21360725 in words is "twenty-one million, three hundred sixty thousand, seven hundred twenty-five".