21423775 has 12 divisors (see below), whose sum is σ = 27132192. Its totient is φ = 16773440.

The previous prime is 21423769. The next prime is 21423781. The reversal of 21423775 is 57732412.

It is an interprime number because it is at equal distance from previous prime (21423769) and next prime (21423781).

It is not a de Polignac number, because 21423775 - 2¹¹ = 21421727 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 11 ways as a sum of consecutive naturals, for example, 7942 + ... + 10291.

It is an arithmetic number, because the mean of its divisors is an integer number (2261016).

Almost surely, 2^21423775 is an apocalyptic number.

21423775 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21423775 is a deficient number, since it is larger than the sum of its proper divisors (5708417).

21423775 is a wasteful number, since it uses less digits than its factorization.

21423775 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18290 (or 18285 counting only the distinct ones).

The product of its digits is 11760, while the sum is 31.

The square root of 21423775 is about 4628.5823963715. The cubic root of 21423775 is about 277.7358868680.

The spelling of 21423775 in words is "twenty-one million, four hundred twenty-three thousand, seven hundred seventy-five".