21283739 has 2 divisors, whose sum is σ = 21283740. Its totient is φ = 21283738.

The previous prime is 21283729. The next prime is 21283751. The reversal of 21283739 is 93738212.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21283739 is a prime.

It is a Chen prime.

It is equal to p_1346777 and since 21283739 and 1346777 have the same sum of digits, it is a Honaker prime.

It is a junction number, because it is equal to n+sod(n) for n = 21283699 and 21283708.

It is not a weakly prime, because it can be changed into another prime (21283729) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10641869 + 10641870.

It is an arithmetic number, because the mean of its divisors is an integer number (10641870).

Almost surely, 2^21283739 is an apocalyptic number.

21283739 is a deficient number, since it is larger than the sum of its proper divisors (1).

21283739 is an equidigital number, since it uses as much as digits as its factorization.

21283739 is an evil number, because the sum of its binary digits is even.

The product of its digits is 18144, while the sum is 35.

The square root of 21283739 is about 4613.4302855901. The cubic root of 21283739 is about 277.1294255443.

It can be divided in two parts, 21283 and 739, that added together give a palindrome (22022).

The spelling of 21283739 in words is "twenty-one million, two hundred eighty-three thousand, seven hundred thirty-nine".