20786749 has 2 divisors, whose sum is σ = 20786750. Its totient is φ = 20786748.

The previous prime is 20786747. The next prime is 20786761. The reversal of 20786749 is 94768702.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19448100 + 1338649 = 4410^2 + 1157^2 .

It is a cyclic number.

It is not a de Polignac number, because 20786749 - 2¹ = 20786747 is a prime.

Together with 20786747, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20786747) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10393374 + 10393375.

It is an arithmetic number, because the mean of its divisors is an integer number (10393375).

Almost surely, 2^20786749 is an apocalyptic number.

It is an amenable number.

20786749 is a deficient number, since it is larger than the sum of its proper divisors (1).

20786749 is an equidigital number, since it uses as much as digits as its factorization.

20786749 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 169344, while the sum is 43.

The square root of 20786749 is about 4559.2487319733. The cubic root of 20786749 is about 274.9553602473.

It can be divided in two parts, 20 and 786749, that added together give a square (786769 = 887²).

The spelling of 20786749 in words is "twenty million, seven hundred eighty-six thousand, seven hundred forty-nine".