21283139 has 2 divisors, whose sum is σ = 21283140. Its totient is φ = 21283138.

The previous prime is 21283127. The next prime is 21283147. The reversal of 21283139 is 93138212.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21283139 is a prime.

It is not a weakly prime, because it can be changed into another prime (21283169) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10641569 + 10641570.

It is an arithmetic number, because the mean of its divisors is an integer number (10641570).

Almost surely, 2^21283139 is an apocalyptic number.

21283139 is a deficient number, since it is larger than the sum of its proper divisors (1).

21283139 is an equidigital number, since it uses as much as digits as its factorization.

21283139 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2592, while the sum is 29.

The square root of 21283139 is about 4613.3652575967. The cubic root of 21283139 is about 277.1268213776.

The spelling of 21283139 in words is "twenty-one million, two hundred eighty-three thousand, one hundred thirty-nine".