21930851 has 2 divisors, whose sum is σ = 21930852. Its totient is φ = 21930850.

The previous prime is 21930809. The next prime is 21930869. The reversal of 21930851 is 15803912.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21930851 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21932851) 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, 10965425 + 10965426.

It is an arithmetic number, because the mean of its divisors is an integer number (10965426).

Almost surely, 2^21930851 is an apocalyptic number.

21930851 is a deficient number, since it is larger than the sum of its proper divisors (1).

21930851 is an equidigital number, since it uses as much as digits as its factorization.

21930851 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2160, while the sum is 29.

The square root of 21930851 is about 4683.0386502783. The cubic root of 21930851 is about 279.9100518902.

The spelling of 21930851 in words is "twenty-one million, nine hundred thirty thousand, eight hundred fifty-one".