21230775 has 48 divisors (see below), whose sum is σ = 39640320. Its totient is φ = 11138400.

The previous prime is 21230767. The next prime is 21230789. The reversal of 21230775 is 57703212.

It is not a de Polignac number, because 21230775 - 2³ = 21230767 is a prime.

It is a hoax number, since the sum of its digits (27) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 47704 + ... + 48146.

It is an arithmetic number, because the mean of its divisors is an integer number (825840).

Almost surely, 2^21230775 is an apocalyptic number.

21230775 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21230775 is a deficient number, since it is larger than the sum of its proper divisors (18409545).

21230775 is a wasteful number, since it uses less digits than its factorization.

21230775 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 533 (or 522 counting only the distinct ones).

The product of its (nonzero) digits is 2940, while the sum is 27.

The square root of 21230775 is about 4607.6865127741. The cubic root of 21230775 is about 276.8993582784.

Adding to 21230775 its reverse (57703212), we get a palindrome (78933987).

The spelling of 21230775 in words is "twenty-one million, two hundred thirty thousand, seven hundred seventy-five".