21090367 has 2 divisors, whose sum is σ = 21090368. Its totient is φ = 21090366.

The previous prime is 21090347. The next prime is 21090371. The reversal of 21090367 is 76309012.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21090367 - 2⁷ = 21090239 is a prime.

It is a Chen prime.

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

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21090347) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10545183 + 10545184.

It is an arithmetic number, because the mean of its divisors is an integer number (10545184).

Almost surely, 2^21090367 is an apocalyptic number.

21090367 is a deficient number, since it is larger than the sum of its proper divisors (1).

21090367 is an equidigital number, since it uses as much as digits as its factorization.

21090367 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2268, while the sum is 28.

The square root of 21090367 is about 4592.4249585595. The cubic root of 21090367 is about 276.2875905522.

Adding to 21090367 its reverse (76309012), we get a palindrome (97399379).

The spelling of 21090367 in words is "twenty-one million, ninety thousand, three hundred sixty-seven".