21359389 has 2 divisors, whose sum is σ = 21359390. Its totient is φ = 21359388.

The previous prime is 21359383. The next prime is 21359413. The reversal of 21359389 is 98395312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19624900 + 1734489 = 4430^2 + 1317^2 .

It is a cyclic number.

It is not a de Polignac number, because 21359389 - 2¹⁵ = 21326621 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21359383) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10679694 + 10679695.

It is an arithmetic number, because the mean of its divisors is an integer number (10679695).

Almost surely, 2^21359389 is an apocalyptic number.

It is an amenable number.

21359389 is a deficient number, since it is larger than the sum of its proper divisors (1).

21359389 is an equidigital number, since it uses as much as digits as its factorization.

21359389 is an evil number, because the sum of its binary digits is even.

The product of its digits is 58320, while the sum is 40.

The square root of 21359389 is about 4621.6219014541. The cubic root of 21359389 is about 277.4573762416.

The spelling of 21359389 in words is "twenty-one million, three hundred fifty-nine thousand, three hundred eighty-nine".