21771125 has 8 divisors (see below), whose sum is σ = 27170520. Its totient is φ = 17416800.

The previous prime is 21771121. The next prime is 21771151. The reversal of 21771125 is 52117712.

It can be written as a sum of positive squares in 4 ways, for example, as 27556 + 21743569 = 166^2 + 4663^2 .

It is not a de Polignac number, because 21771125 - 2² = 21771121 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21771094 and 21771103.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21771121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 86960 + ... + 87209.

It is an arithmetic number, because the mean of its divisors is an integer number (3396315).

Almost surely, 2^21771125 is an apocalyptic number.

21771125 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21771125 is a deficient number, since it is larger than the sum of its proper divisors (5399395).

21771125 is an equidigital number, since it uses as much as digits as its factorization.

21771125 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 174184 (or 174174 counting only the distinct ones).

The product of its digits is 980, while the sum is 26.

The square root of 21771125 is about 4665.9538146021. The cubic root of 21771125 is about 279.2288517692.

Adding to 21771125 its reverse (52117712), we get a palindrome (73888837).

The spelling of 21771125 in words is "twenty-one million, seven hundred seventy-one thousand, one hundred twenty-five".