21963287 has 2 divisors, whose sum is σ = 21963288. Its totient is φ = 21963286.

The previous prime is 21963257. The next prime is 21963313. The reversal of 21963287 is 78236912.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21963287 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21963287.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21963247) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10981643 + 10981644.

It is an arithmetic number, because the mean of its divisors is an integer number (10981644).

Almost surely, 2^21963287 is an apocalyptic number.

21963287 is a deficient number, since it is larger than the sum of its proper divisors (1).

21963287 is an equidigital number, since it uses as much as digits as its factorization.

21963287 is an evil number, because the sum of its binary digits is even.

The product of its digits is 36288, while the sum is 38.

The square root of 21963287 is about 4686.5005067748. The cubic root of 21963287 is about 280.0479807231.

The spelling of 21963287 in words is "twenty-one million, nine hundred sixty-three thousand, two hundred eighty-seven".