21310889 has 2 divisors, whose sum is σ = 21310890. Its totient is φ = 21310888.

The previous prime is 21310871. The next prime is 21310901. The reversal of 21310889 is 98801312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19009600 + 2301289 = 4360^2 + 1517^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21310889 is a prime.

It is not a weakly prime, because it can be changed into another prime (21310819) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10655444 + 10655445.

It is an arithmetic number, because the mean of its divisors is an integer number (10655445).

Almost surely, 2^21310889 is an apocalyptic number.

It is an amenable number.

21310889 is a deficient number, since it is larger than the sum of its proper divisors (1).

21310889 is an equidigital number, since it uses as much as digits as its factorization.

21310889 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3456, while the sum is 32.

The square root of 21310889 is about 4616.3718437752. The cubic root of 21310889 is about 277.2472129137.

The spelling of 21310889 in words is "twenty-one million, three hundred ten thousand, eight hundred eighty-nine".