21651683 has 2 divisors, whose sum is σ = 21651684. Its totient is φ = 21651682.

The previous prime is 21651667. The next prime is 21651689. The reversal of 21651683 is 38615612.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21651683 - 2⁴ = 21651667 is a prime.

It is not a weakly prime, because it can be changed into another prime (21651689) by changing a digit.

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

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10825841 + 10825842.

It is an arithmetic number, because the mean of its divisors is an integer number (10825842).

Almost surely, 2^21651683 is an apocalyptic number.

21651683 is a deficient number, since it is larger than the sum of its proper divisors (1).

21651683 is an equidigital number, since it uses as much as digits as its factorization.

21651683 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 8640, while the sum is 32.

The square root of 21651683 is about 4653.1368989102. The cubic root of 21651683 is about 278.7172746074.

The spelling of 21651683 in words is "twenty-one million, six hundred fifty-one thousand, six hundred eighty-three".