21768275 has 6 divisors (see below), whose sum is σ = 26992692. Its totient is φ = 17414600.

The previous prime is 21768269. The next prime is 21768289. The reversal of 21768275 is 57286712.

21768275 = T₄₆₂ + T₄₆₃ + ... + T₆₁₁.

It is not a de Polignac number, because 21768275 - 2¹² = 21764179 is a prime.

It is a Duffinian 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, 435341 + ... + 435390.

It is an arithmetic number, because the mean of its divisors is an integer number (4498782).

Almost surely, 2^21768275 is an apocalyptic number.

21768275 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21768275 is a deficient number, since it is larger than the sum of its proper divisors (5224417).

21768275 is an equidigital number, since it uses as much as digits as its factorization.

21768275 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 870741 (or 870736 counting only the distinct ones).

The product of its digits is 47040, while the sum is 38.

The square root of 21768275 is about 4665.6484008120. The cubic root of 21768275 is about 279.2166668690.

The spelling of 21768275 in words is "twenty-one million, seven hundred sixty-eight thousand, two hundred seventy-five".