21968567 has 2 divisors, whose sum is σ = 21968568. Its totient is φ = 21968566.

The previous prime is 21968549. The next prime is 21968603. The reversal of 21968567 is 76586912.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21968567 - 2¹⁶ = 21903031 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21968867) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10984283 + 10984284.

It is an arithmetic number, because the mean of its divisors is an integer number (10984284).

Almost surely, 2^21968567 is an apocalyptic number.

21968567 is a deficient number, since it is larger than the sum of its proper divisors (1).

21968567 is an equidigital number, since it uses as much as digits as its factorization.

21968567 is an evil number, because the sum of its binary digits is even.

The product of its digits is 181440, while the sum is 44.

The square root of 21968567 is about 4687.0637930372. The cubic root of 21968567 is about 280.0704202129.

It can be divided in two parts, 219 and 68567, that added together give a palindrome (68786).

The spelling of 21968567 in words is "twenty-one million, nine hundred sixty-eight thousand, five hundred sixty-seven".