21371725 has 6 divisors (see below), whose sum is σ = 26500970. Its totient is φ = 17097360.

The previous prime is 21371717. The next prime is 21371759. The reversal of 21371725 is 52717312.

It can be written as a sum of positive squares in 3 ways, for example, as 1844164 + 19527561 = 1358^2 + 4419^2 .

It is not a de Polignac number, because 21371725 - 2³ = 21371717 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21371693 and 21371702.

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, 427410 + ... + 427459.

Almost surely, 2^21371725 is an apocalyptic number.

21371725 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21371725 is a deficient number, since it is larger than the sum of its proper divisors (5129245).

21371725 is an equidigital number, since it uses as much as digits as its factorization.

21371725 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 854879 (or 854874 counting only the distinct ones).

The product of its digits is 2940, while the sum is 28.

The square root of 21371725 is about 4622.9563052229. The cubic root of 21371725 is about 277.5107806325.

The spelling of 21371725 in words is "twenty-one million, three hundred seventy-one thousand, seven hundred twenty-five".