21430369 has 2 divisors, whose sum is σ = 21430370. Its totient is φ = 21430368.

The previous prime is 21430327. The next prime is 21430379. The reversal of 21430369 is 96303412.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20142144 + 1288225 = 4488^2 + 1135^2 .

It is a cyclic number.

It is not a de Polignac number, because 21430369 - 2¹⁵ = 21397601 is a prime.

It is a super-2 number, since 2×21430369² = 918521430952322, which contains 22 as substring.

It is a Chen prime.

It is an alternating number because its digits alternate between even and odd.

It is not a weakly prime, because it can be changed into another prime (21430379) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10715184 + 10715185.

It is an arithmetic number, because the mean of its divisors is an integer number (10715185).

Almost surely, 2^21430369 is an apocalyptic number.

It is an amenable number.

21430369 is a deficient number, since it is larger than the sum of its proper divisors (1).

21430369 is an equidigital number, since it uses as much as digits as its factorization.

21430369 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3888, while the sum is 28.

The square root of 21430369 is about 4629.2946546963. The cubic root of 21430369 is about 277.7643786189.

The spelling of 21430369 in words is "twenty-one million, four hundred thirty thousand, three hundred sixty-nine".