21984967 has 2 divisors, whose sum is σ = 21984968. Its totient is φ = 21984966.

The previous prime is 21984947. The next prime is 21985009. The reversal of 21984967 is 76948912.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21984967 - 2¹⁵ = 21952199 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21984917) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10992483 + 10992484.

It is an arithmetic number, because the mean of its divisors is an integer number (10992484).

Almost surely, 2^21984967 is an apocalyptic number.

21984967 is a deficient number, since it is larger than the sum of its proper divisors (1).

21984967 is an equidigital number, since it uses as much as digits as its factorization.

21984967 is an evil number, because the sum of its binary digits is even.

The product of its digits is 217728, while the sum is 46.

The square root of 21984967 is about 4688.8129627871. The cubic root of 21984967 is about 280.1400957089.

The spelling of 21984967 in words is "twenty-one million, nine hundred eighty-four thousand, nine hundred sixty-seven".