21916511 has 2 divisors, whose sum is σ = 21916512. Its totient is φ = 21916510.

The previous prime is 21916483. The next prime is 21916513. The reversal of 21916511 is 11561912.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21916511 - 2¹⁴ = 21900127 is a prime.

Together with 21916513, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21916513) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10958255 + 10958256.

It is an arithmetic number, because the mean of its divisors is an integer number (10958256).

Almost surely, 2^21916511 is an apocalyptic number.

21916511 is a deficient number, since it is larger than the sum of its proper divisors (1).

21916511 is an equidigital number, since it uses as much as digits as its factorization.

21916511 is an evil number, because the sum of its binary digits is even.

The product of its digits is 540, while the sum is 26.

The square root of 21916511 is about 4681.5073427263. The cubic root of 21916511 is about 279.8490300094.

The spelling of 21916511 in words is "twenty-one million, nine hundred sixteen thousand, five hundred eleven".