21150491 has 2 divisors, whose sum is σ = 21150492. Its totient is φ = 21150490.

The previous prime is 21150487. The next prime is 21150523. The reversal of 21150491 is 19405112.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21150491 - 2² = 21150487 is a prime.

It is not a weakly prime, because it can be changed into another prime (21150191) 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, 10575245 + 10575246.

It is an arithmetic number, because the mean of its divisors is an integer number (10575246).

Almost surely, 2^21150491 is an apocalyptic number.

21150491 is a deficient number, since it is larger than the sum of its proper divisors (1).

21150491 is an equidigital number, since it uses as much as digits as its factorization.

21150491 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 360, while the sum is 23.

The square root of 21150491 is about 4598.9662968976. The cubic root of 21150491 is about 276.5498865219.

The spelling of 21150491 in words is "twenty-one million, one hundred fifty thousand, four hundred ninety-one".