21919907 has 6 divisors (see below), whose sum is σ = 22398468. Its totient is φ = 21451364.

The previous prime is 21919903. The next prime is 21919927. The reversal of 21919907 is 70991912.

It is not a de Polignac number, because 21919907 - 2² = 21919903 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21919903) 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, 2753 + ... + 7170.

It is an arithmetic number, because the mean of its divisors is an integer number (3733078).

Almost surely, 2^21919907 is an apocalyptic number.

21919907 is a deficient number, since it is larger than the sum of its proper divisors (478561).

21919907 is an frugal number, since it uses more digits than its factorization.

21919907 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10017 (or 9970 counting only the distinct ones).

The product of its (nonzero) digits is 10206, while the sum is 38.

The square root of 21919907 is about 4681.8700323695. The cubic root of 21919907 is about 279.8634836212.

The spelling of 21919907 in words is "twenty-one million, nine hundred nineteen thousand, nine hundred seven".