21831851 has 2 divisors, whose sum is σ = 21831852. Its totient is φ = 21831850.

The previous prime is 21831841. The next prime is 21831863. The reversal of 21831851 is 15813812.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21831851 - 2⁶ = 21831787 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21831811) 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, 10915925 + 10915926.

It is an arithmetic number, because the mean of its divisors is an integer number (10915926).

Almost surely, 2^21831851 is an apocalyptic number.

21831851 is a deficient number, since it is larger than the sum of its proper divisors (1).

21831851 is an equidigital number, since it uses as much as digits as its factorization.

21831851 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1920, while the sum is 29.

The square root of 21831851 is about 4672.4566343627. The cubic root of 21831851 is about 279.4882275884.

The spelling of 21831851 in words is "twenty-one million, eight hundred thirty-one thousand, eight hundred fifty-one".