20947783 has 2 divisors, whose sum is σ = 20947784. Its totient is φ = 20947782.

The previous prime is 20947781. The next prime is 20947793. The reversal of 20947783 is 38774902.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20947783 - 2¹ = 20947781 is a prime.

It is a super-2 number, since 2×20947783² = 877619225230178, which contains 22 as substring.

Together with 20947781, 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 (20947781) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10473891 + 10473892.

It is an arithmetic number, because the mean of its divisors is an integer number (10473892).

Almost surely, 2^20947783 is an apocalyptic number.

20947783 is a deficient number, since it is larger than the sum of its proper divisors (1).

20947783 is an equidigital number, since it uses as much as digits as its factorization.

20947783 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 84672, while the sum is 40.

The square root of 20947783 is about 4576.8748071146. The cubic root of 20947783 is about 275.6635568221.

The spelling of 20947783 in words is "twenty million, nine hundred forty-seven thousand, seven hundred eighty-three".