21227897 has 2 divisors, whose sum is σ = 21227898. Its totient is φ = 21227896.

The previous prime is 21227891. The next prime is 21227911. The reversal of 21227897 is 79872212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17131321 + 4096576 = 4139^2 + 2024^2 .

It is a cyclic number.

It is not a de Polignac number, because 21227897 - 2²⁴ = 4450681 is a prime.

It is a super-2 number, since 2×21227897² = 901247222085218, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21227897.

It is not a weakly prime, because it can be changed into another prime (21227891) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10613948 + 10613949.

It is an arithmetic number, because the mean of its divisors is an integer number (10613949).

Almost surely, 2^21227897 is an apocalyptic number.

It is an amenable number.

21227897 is a deficient number, since it is larger than the sum of its proper divisors (1).

21227897 is an equidigital number, since it uses as much as digits as its factorization.

21227897 is an evil number, because the sum of its binary digits is even.

The product of its digits is 28224, while the sum is 38.

The square root of 21227897 is about 4607.3741979570. The cubic root of 21227897 is about 276.8868457446.

The spelling of 21227897 in words is "twenty-one million, two hundred twenty-seven thousand, eight hundred ninety-seven".