21919775 has 6 divisors (see below), whose sum is σ = 27180552. Its totient is φ = 17535800.

The previous prime is 21919771. The next prime is 21919811. The reversal of 21919775 is 57791912.

It is a happy number.

It is not a de Polignac number, because 21919775 - 2² = 21919771 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21919771) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 438371 + ... + 438420.

It is an arithmetic number, because the mean of its divisors is an integer number (4530092).

Almost surely, 2^21919775 is an apocalyptic number.

21919775 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21919775 is a deficient number, since it is larger than the sum of its proper divisors (5260777).

21919775 is an equidigital number, since it uses as much as digits as its factorization.

21919775 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 876801 (or 876796 counting only the distinct ones).

The product of its digits is 39690, while the sum is 41.

The square root of 21919775 is about 4681.8559354171. The cubic root of 21919775 is about 279.8629218479.

The spelling of 21919775 in words is "twenty-one million, nine hundred nineteen thousand, seven hundred seventy-five".