21333779 has 2 divisors, whose sum is σ = 21333780. Its totient is φ = 21333778.

The previous prime is 21333773. The next prime is 21333839. The reversal of 21333779 is 97733312.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21333779 - 2¹² = 21329683 is a prime.

It is a Chen prime.

It is equal to p_1349729 and since 21333779 and 1349729 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (21333773) 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, 10666889 + 10666890.

It is an arithmetic number, because the mean of its divisors is an integer number (10666890).

Almost surely, 2^21333779 is an apocalyptic number.

21333779 is a deficient number, since it is larger than the sum of its proper divisors (1).

21333779 is an equidigital number, since it uses as much as digits as its factorization.

21333779 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 23814, while the sum is 35.

The square root of 21333779 is about 4618.8503980969. The cubic root of 21333779 is about 277.3464410269.

The spelling of 21333779 in words is "twenty-one million, three hundred thirty-three thousand, seven hundred seventy-nine".