21304775 has 6 divisors (see below), whose sum is σ = 26417952. Its totient is φ = 17043800.

The previous prime is 21304753. The next prime is 21304783. The reversal of 21304775 is 57740312.

21304775 = T₁₂₉₃ + T₁₂₉₄ + ... + T₁₃₁₇.

It is not a de Polignac number, because 21304775 - 2¹² = 21300679 is a prime.

It is a Duffinian number.

It is a congruent 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, 426071 + ... + 426120.

It is an arithmetic number, because the mean of its divisors is an integer number (4402992).

Almost surely, 2^21304775 is an apocalyptic number.

21304775 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21304775 is a deficient number, since it is larger than the sum of its proper divisors (5113177).

21304775 is an equidigital number, since it uses as much as digits as its factorization.

21304775 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 852201 (or 852196 counting only the distinct ones).

The product of its (nonzero) digits is 5880, while the sum is 29.

The square root of 21304775 is about 4615.7095879182. The cubic root of 21304775 is about 277.2206967105.

The spelling of 21304775 in words is "twenty-one million, three hundred four thousand, seven hundred seventy-five".