21299371 has 2 divisors, whose sum is σ = 21299372. Its totient is φ = 21299370.

The previous prime is 21299329. The next prime is 21299381. The reversal of 21299371 is 17399212.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21299371 - 2⁹ = 21298859 is a prime.

It is not a weakly prime, because it can be changed into another prime (21299321) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10649685 + 10649686.

It is an arithmetic number, because the mean of its divisors is an integer number (10649686).

Almost surely, 2^21299371 is an apocalyptic number.

21299371 is a deficient number, since it is larger than the sum of its proper divisors (1).

21299371 is an equidigital number, since it uses as much as digits as its factorization.

21299371 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6804, while the sum is 34.

The square root of 21299371 is about 4615.1241586766. The cubic root of 21299371 is about 277.1972555285.

The spelling of 21299371 in words is "twenty-one million, two hundred ninety-nine thousand, three hundred seventy-one".