21771325 has 6 divisors (see below), whose sum is σ = 26996474. Its totient is φ = 17417040.

The previous prime is 21771313. The next prime is 21771329. The reversal of 21771325 is 52317712.

It can be written as a sum of positive squares in 3 ways, for example, as 1223236 + 20548089 = 1106^2 + 4533^2 .

It is a de Polignac number, because none of the positive numbers 2^k-21771325 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21771293 and 21771302.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21771329) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 435402 + ... + 435451.

Almost surely, 2^21771325 is an apocalyptic number.

21771325 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21771325 is a deficient number, since it is larger than the sum of its proper divisors (5225149).

21771325 is an equidigital number, since it uses as much as digits as its factorization.

21771325 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 870863 (or 870858 counting only the distinct ones).

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

The square root of 21771325 is about 4665.9752463981. The cubic root of 21771325 is about 279.2297068100.

The spelling of 21771325 in words is "twenty-one million, seven hundred seventy-one thousand, three hundred twenty-five".