21982787 has 2 divisors, whose sum is σ = 21982788. Its totient is φ = 21982786.

The previous prime is 21982781. The next prime is 21982789. The reversal of 21982787 is 78728912.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21982787 - 2⁸ = 21982531 is a prime.

Together with 21982789, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21982781) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10991393 + 10991394.

It is an arithmetic number, because the mean of its divisors is an integer number (10991394).

Almost surely, 2^21982787 is an apocalyptic number.

21982787 is a deficient number, since it is larger than the sum of its proper divisors (1).

21982787 is an equidigital number, since it uses as much as digits as its factorization.

21982787 is an evil number, because the sum of its binary digits is even.

The product of its digits is 112896, while the sum is 44.

The square root of 21982787 is about 4688.5804888047. The cubic root of 21982787 is about 280.1308359634.

The spelling of 21982787 in words is "twenty-one million, nine hundred eighty-two thousand, seven hundred eighty-seven".