21151307 has 2 divisors, whose sum is σ = 21151308. Its totient is φ = 21151306.

The previous prime is 21151303. The next prime is 21151343. The reversal of 21151307 is 70315112.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21151307 - 2² = 21151303 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21151303) 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, 10575653 + 10575654.

It is an arithmetic number, because the mean of its divisors is an integer number (10575654).

Almost surely, 2^21151307 is an apocalyptic number.

21151307 is a deficient number, since it is larger than the sum of its proper divisors (1).

21151307 is an equidigital number, since it uses as much as digits as its factorization.

21151307 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 210, while the sum is 20.

The square root of 21151307 is about 4599.0550116301. The cubic root of 21151307 is about 276.5534429690.

Adding to 21151307 its reverse (70315112), we get a palindrome (91466419).

The spelling of 21151307 in words is "twenty-one million, one hundred fifty-one thousand, three hundred seven".