21163291 has 2 divisors, whose sum is σ = 21163292. Its totient is φ = 21163290.

The previous prime is 21163253. The next prime is 21163309. The reversal of 21163291 is 19236112.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21163291 is a prime.

It is not a weakly prime, because it can be changed into another prime (21163201) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10581645 + 10581646.

It is an arithmetic number, because the mean of its divisors is an integer number (10581646).

Almost surely, 2^21163291 is an apocalyptic number.

21163291 is a deficient number, since it is larger than the sum of its proper divisors (1).

21163291 is an equidigital number, since it uses as much as digits as its factorization.

21163291 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 648, while the sum is 25.

The square root of 21163291 is about 4600.3577034835. The cubic root of 21163291 is about 276.6056633941.

The spelling of 21163291 in words is "twenty-one million, one hundred sixty-three thousand, two hundred ninety-one".