20769857 has 2 divisors, whose sum is σ = 20769858. Its totient is φ = 20769856.

The previous prime is 20769823. The next prime is 20769863. The reversal of 20769857 is 75896702.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14737921 + 6031936 = 3839^2 + 2456^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20769857 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (20769757) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10384928 + 10384929.

It is an arithmetic number, because the mean of its divisors is an integer number (10384929).

Almost surely, 2^20769857 is an apocalyptic number.

It is an amenable number.

20769857 is a deficient number, since it is larger than the sum of its proper divisors (1).

20769857 is an equidigital number, since it uses as much as digits as its factorization.

20769857 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 211680, while the sum is 44.

The square root of 20769857 is about 4557.3958572852. The cubic root of 20769857 is about 274.8808607891.

The spelling of 20769857 in words is "twenty million, seven hundred sixty-nine thousand, eight hundred fifty-seven".