21986273 has 2 divisors, whose sum is σ = 21986274. Its totient is φ = 21986272.

The previous prime is 21986269. The next prime is 21986309. The reversal of 21986273 is 37268912.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19651489 + 2334784 = 4433^2 + 1528^2 .

It is a cyclic number.

It is not a de Polignac number, because 21986273 - 2² = 21986269 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (21986203) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10993136 + 10993137.

It is an arithmetic number, because the mean of its divisors is an integer number (10993137).

Almost surely, 2^21986273 is an apocalyptic number.

It is an amenable number.

21986273 is a deficient number, since it is larger than the sum of its proper divisors (1).

21986273 is an equidigital number, since it uses as much as digits as its factorization.

21986273 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 21986273 is about 4688.9522283768. The cubic root of 21986273 is about 280.1456427678.

The spelling of 21986273 in words is "twenty-one million, nine hundred eighty-six thousand, two hundred seventy-three".