21149663 has 2 divisors, whose sum is σ = 21149664. Its totient is φ = 21149662.

The previous prime is 21149659. The next prime is 21149699. The reversal of 21149663 is 36694112.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21149663 - 2² = 21149659 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 (21140663) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10574831 + 10574832.

It is an arithmetic number, because the mean of its divisors is an integer number (10574832).

Almost surely, 2^21149663 is an apocalyptic number.

21149663 is a deficient number, since it is larger than the sum of its proper divisors (1).

21149663 is an equidigital number, since it uses as much as digits as its factorization.

21149663 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7776, while the sum is 32.

The square root of 21149663 is about 4598.8762757874. The cubic root of 21149663 is about 276.5462776806.

It can be divided in two parts, 21149 and 663, that added together give a palindrome (21812).

The spelling of 21149663 in words is "twenty-one million, one hundred forty-nine thousand, six hundred sixty-three".