21633149 has 2 divisors, whose sum is σ = 21633150. Its totient is φ = 21633148.

The previous prime is 21633127. The next prime is 21633151. The reversal of 21633149 is 94133612.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21436900 + 196249 = 4630^2 + 443^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21633149 is a prime.

Together with 21633151, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21633119) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10816574 + 10816575.

It is an arithmetic number, because the mean of its divisors is an integer number (10816575).

Almost surely, 2^21633149 is an apocalyptic number.

It is an amenable number.

21633149 is a deficient number, since it is larger than the sum of its proper divisors (1).

21633149 is an equidigital number, since it uses as much as digits as its factorization.

21633149 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3888, while the sum is 29.

The square root of 21633149 is about 4651.1449128145. The cubic root of 21633149 is about 278.6377238916.

The spelling of 21633149 in words is "twenty-one million, six hundred thirty-three thousand, one hundred forty-nine".