21947075 has 6 divisors (see below), whose sum is σ = 27214404. Its totient is φ = 17557640.

The previous prime is 21947063. The next prime is 21947077. The reversal of 21947075 is 57074912.

It is not a de Polignac number, because 21947075 - 2⁴ = 21947059 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21947077) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 438917 + ... + 438966.

It is an arithmetic number, because the mean of its divisors is an integer number (4535734).

Almost surely, 2^21947075 is an apocalyptic number.

21947075 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21947075 is a deficient number, since it is larger than the sum of its proper divisors (5267329).

21947075 is an equidigital number, since it uses as much as digits as its factorization.

21947075 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 877893 (or 877888 counting only the distinct ones).

The product of its (nonzero) digits is 17640, while the sum is 35.

The square root of 21947075 is about 4684.7705386710. The cubic root of 21947075 is about 279.9790588080.

The spelling of 21947075 in words is "twenty-one million, nine hundred forty-seven thousand, seventy-five".