21903967 has 4 divisors (see below), whose sum is σ = 21920440. Its totient is φ = 21887496.

The previous prime is 21903943. The next prime is 21903983. The reversal of 21903967 is 76930912.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21903967 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 (21903907) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6048 + ... + 8965.

It is an arithmetic number, because the mean of its divisors is an integer number (5480110).

Almost surely, 2^21903967 is an apocalyptic number.

21903967 is a deficient number, since it is larger than the sum of its proper divisors (16473).

21903967 is a wasteful number, since it uses less digits than its factorization.

21903967 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16472.

The product of its (nonzero) digits is 20412, while the sum is 37.

The square root of 21903967 is about 4680.1674115356. The cubic root of 21903967 is about 279.7956289277.

The spelling of 21903967 in words is "twenty-one million, nine hundred three thousand, nine hundred sixty-seven".