21755275 has 6 divisors (see below), whose sum is σ = 26976572. Its totient is φ = 17404200.

The previous prime is 21755267. The next prime is 21755329. The reversal of 21755275 is 57255712.

It is not a de Polignac number, because 21755275 - 2³ = 21755267 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21755275.

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, 435081 + ... + 435130.

Almost surely, 2^21755275 is an apocalyptic number.

21755275 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21755275 is a deficient number, since it is larger than the sum of its proper divisors (5221297).

21755275 is an equidigital number, since it uses as much as digits as its factorization.

21755275 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 870221 (or 870216 counting only the distinct ones).

The product of its digits is 24500, while the sum is 34.

The square root of 21755275 is about 4664.2550316208. The cubic root of 21755275 is about 279.1610731287.

The spelling of 21755275 in words is "twenty-one million, seven hundred fifty-five thousand, two hundred seventy-five".