21864967 has 4 divisors (see below), whose sum is σ = 21874320. Its totient is φ = 21855616.

The previous prime is 21864959. The next prime is 21864989. The reversal of 21864967 is 76946812.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 21864967 - 2³ = 21864959 is a prime.

It is a super-2 number, since 2×21864967² = 956153563822178, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21865967) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2334 + ... + 7012.

It is an arithmetic number, because the mean of its divisors is an integer number (5468580).

Almost surely, 2^21864967 is an apocalyptic number.

21864967 is a deficient number, since it is larger than the sum of its proper divisors (9353).

21864967 is an equidigital number, since it uses as much as digits as its factorization.

21864967 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9352.

The product of its digits is 145152, while the sum is 43.

The square root of 21864967 is about 4675.9990376389. Note that the first 3 decimals coincide. The cubic root of 21864967 is about 279.6294716250.

The spelling of 21864967 in words is "twenty-one million, eight hundred sixty-four thousand, nine hundred sixty-seven".