21727025 has 6 divisors (see below), whose sum is σ = 26941542. Its totient is φ = 17381600.

The previous prime is 21727009. The next prime is 21727081. The reversal of 21727025 is 52072712.

It can be written as a sum of positive squares in 3 ways, for example, as 5340721 + 16386304 = 2311^2 + 4048^2 .

It is not a de Polignac number, because 21727025 - 2⁴ = 21727009 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21726985 and 21727003.

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, 434516 + ... + 434565.

It is an arithmetic number, because the mean of its divisors is an integer number (4490257).

Almost surely, 2^21727025 is an apocalyptic number.

21727025 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21727025 is a deficient number, since it is larger than the sum of its proper divisors (5214517).

21727025 is an equidigital number, since it uses as much as digits as its factorization.

21727025 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 869091 (or 869086 counting only the distinct ones).

The product of its (nonzero) digits is 1960, while the sum is 26.

The square root of 21727025 is about 4661.2256971745. The cubic root of 21727025 is about 279.0401872542.

Adding to 21727025 its reverse (52072712), we get a palindrome (73799737).

The spelling of 21727025 in words is "twenty-one million, seven hundred twenty-seven thousand, twenty-five".