21782039 has 2 divisors, whose sum is σ = 21782040. Its totient is φ = 21782038.

The previous prime is 21782017. The next prime is 21782051. The reversal of 21782039 is 93028712.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21782039 - 2¹⁶ = 21716503 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 21781996 and 21782014.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21782069) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10891019 + 10891020.

It is an arithmetic number, because the mean of its divisors is an integer number (10891020).

Almost surely, 2^21782039 is an apocalyptic number.

21782039 is a deficient number, since it is larger than the sum of its proper divisors (1).

21782039 is an equidigital number, since it uses as much as digits as its factorization.

21782039 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 6048, while the sum is 32.

The square root of 21782039 is about 4667.1232038591. The cubic root of 21782039 is about 279.2755036929.

The spelling of 21782039 in words is "twenty-one million, seven hundred eighty-two thousand, thirty-nine".