21799567 has 2 divisors, whose sum is σ = 21799568. Its totient is φ = 21799566.

The previous prime is 21799553. The next prime is 21799597. The reversal of 21799567 is 76599712.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21799567 - 2⁷ = 21799439 is a prime.

It is a super-2 number, since 2×21799567² = 950442242774978, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21799507) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10899783 + 10899784.

It is an arithmetic number, because the mean of its divisors is an integer number (10899784).

Almost surely, 2^21799567 is an apocalyptic number.

21799567 is a deficient number, since it is larger than the sum of its proper divisors (1).

21799567 is an equidigital number, since it uses as much as digits as its factorization.

21799567 is an evil number, because the sum of its binary digits is even.

The product of its digits is 238140, while the sum is 46.

The square root of 21799567 is about 4669.0006425358. Note that the first 3 decimals coincide. The cubic root of 21799567 is about 279.3503945785.

It can be divided in two parts, 21799 and 567, that added together give a triangular number (22366 = T₂₁₁).

The spelling of 21799567 in words is "twenty-one million, seven hundred ninety-nine thousand, five hundred sixty-seven".