21866797 has 8 divisors (see below), whose sum is σ = 22553856. Its totient is φ = 21189072.

The previous prime is 21866773. The next prime is 21866809. The reversal of 21866797 is 79766812.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21866797 is a prime.

It is a super-2 number, since 2×21866797² = 956313622078418, 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 (21866737) 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 7 ways as a sum of consecutive naturals, for example, 2583 + ... + 7099.

It is an arithmetic number, because the mean of its divisors is an integer number (2819232).

Almost surely, 2^21866797 is an apocalyptic number.

It is an amenable number.

21866797 is a deficient number, since it is larger than the sum of its proper divisors (687059).

21866797 is a wasteful number, since it uses less digits than its factorization.

21866797 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4667.

The product of its digits is 254016, while the sum is 46.

The square root of 21866797 is about 4676.1947136534. The cubic root of 21866797 is about 279.6372726530.

The spelling of 21866797 in words is "twenty-one million, eight hundred sixty-six thousand, seven hundred ninety-seven".