20728783 has 2 divisors, whose sum is σ = 20728784. Its totient is φ = 20728782.

The previous prime is 20728781. The next prime is 20728787. The reversal of 20728783 is 38782702.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20728783 - 2¹ = 20728781 is a prime.

It is a super-2 number, since 2×20728783² = 859364889322178, which contains 22 as substring.

Together with 20728781, 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 (20728781) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10364391 + 10364392.

It is an arithmetic number, because the mean of its divisors is an integer number (10364392).

Almost surely, 2^20728783 is an apocalyptic number.

20728783 is a deficient number, since it is larger than the sum of its proper divisors (1).

20728783 is an equidigital number, since it uses as much as digits as its factorization.

20728783 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 37632, while the sum is 37.

The square root of 20728783 is about 4552.8873256429. The cubic root of 20728783 is about 274.6995418188.

The spelling of 20728783 in words is "twenty million, seven hundred twenty-eight thousand, seven hundred eighty-three".