21930371 has 2 divisors, whose sum is σ = 21930372. Its totient is φ = 21930370.

The previous prime is 21930347. The next prime is 21930379. The reversal of 21930371 is 17303912.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21930371 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21930371.

It is not a weakly prime, because it can be changed into another prime (21930379) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10965185 + 10965186.

It is an arithmetic number, because the mean of its divisors is an integer number (10965186).

Almost surely, 2^21930371 is an apocalyptic number.

21930371 is a deficient number, since it is larger than the sum of its proper divisors (1).

21930371 is an equidigital number, since it uses as much as digits as its factorization.

21930371 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1134, while the sum is 26.

The square root of 21930371 is about 4682.9874012216. The cubic root of 21930371 is about 279.9080097471.

The spelling of 21930371 in words is "twenty-one million, nine hundred thirty thousand, three hundred seventy-one".