21833857 has 2 divisors, whose sum is σ = 21833858. Its totient is φ = 21833856.

The previous prime is 21833821. The next prime is 21833863. The reversal of 21833857 is 75833812.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20647936 + 1185921 = 4544^2 + 1089^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21833857 is a prime.

It is a super-2 number, since 2×21833857² = 953434622992898, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21833807) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10916928 + 10916929.

It is an arithmetic number, because the mean of its divisors is an integer number (10916929).

Almost surely, 2^21833857 is an apocalyptic number.

It is an amenable number.

21833857 is a deficient number, since it is larger than the sum of its proper divisors (1).

21833857 is an equidigital number, since it uses as much as digits as its factorization.

21833857 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 40320, while the sum is 37.

The square root of 21833857 is about 4672.6712916703. The cubic root of 21833857 is about 279.4967875011.

The spelling of 21833857 in words is "twenty-one million, eight hundred thirty-three thousand, eight hundred fifty-seven".