21623275 has 12 divisors (see below), whose sum is σ = 27678784. Its totient is φ = 16740000.

The previous prime is 21623267. The next prime is 21623279. The reversal of 21623275 is 57232612.

It is not a de Polignac number, because 21623275 - 2³ = 21623267 is a prime.

It is a hoax number, since the sum of its digits (28) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (21623279) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 13176 + ... + 14725.

Almost surely, 2^21623275 is an apocalyptic number.

21623275 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21623275 is a deficient number, since it is larger than the sum of its proper divisors (6055509).

21623275 is a wasteful number, since it uses less digits than its factorization.

21623275 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27942 (or 27937 counting only the distinct ones).

The product of its digits is 5040, while the sum is 28.

The square root of 21623275 is about 4650.0833325866. The cubic root of 21623275 is about 278.5953246462.

Adding to 21623275 its reverse (57232612), we get a palindrome (78855887).

The spelling of 21623275 in words is "twenty-one million, six hundred twenty-three thousand, two hundred seventy-five".