21911273 has 2 divisors, whose sum is σ = 21911274. Its totient is φ = 21911272.

The previous prime is 21911257. The next prime is 21911291. The reversal of 21911273 is 37211912.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20403289 + 1507984 = 4517^2 + 1228^2 .

It is a cyclic number.

It is not a de Polignac number, because 21911273 - 2⁴ = 21911257 is a prime.

It is not a weakly prime, because it can be changed into another prime (21911213) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10955636 + 10955637.

It is an arithmetic number, because the mean of its divisors is an integer number (10955637).

Almost surely, 2^21911273 is an apocalyptic number.

It is an amenable number.

21911273 is a deficient number, since it is larger than the sum of its proper divisors (1).

21911273 is an equidigital number, since it uses as much as digits as its factorization.

21911273 is an evil number, because the sum of its binary digits is even.

The product of its digits is 756, while the sum is 26.

The square root of 21911273 is about 4680.9478740956. The cubic root of 21911273 is about 279.8267337900.

The spelling of 21911273 in words is "twenty-one million, nine hundred eleven thousand, two hundred seventy-three".