21884987 has 2 divisors, whose sum is σ = 21884988. Its totient is φ = 21884986.

The previous prime is 21884981. The next prime is 21885013. The reversal of 21884987 is 78948812.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21884987 - 2¹⁴ = 21868603 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21884981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10942493 + 10942494.

It is an arithmetic number, because the mean of its divisors is an integer number (10942494).

Almost surely, 2^21884987 is an apocalyptic number.

21884987 is a deficient number, since it is larger than the sum of its proper divisors (1).

21884987 is an equidigital number, since it uses as much as digits as its factorization.

21884987 is an evil number, because the sum of its binary digits is even.

The product of its digits is 258048, while the sum is 47.

The square root of 21884987 is about 4678.1392668453. The cubic root of 21884987 is about 279.7147903648.

The spelling of 21884987 in words is "twenty-one million, eight hundred eighty-four thousand, nine hundred eighty-seven".