20757757 has 2 divisors, whose sum is σ = 20757758. Its totient is φ = 20757756.

The previous prime is 20757749. The next prime is 20757791. The reversal of 20757757 is 75775702.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20602521 + 155236 = 4539^2 + 394^2 .

It is a cyclic number.

It is not a de Polignac number, because 20757757 - 2³ = 20757749 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20757727) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10378878 + 10378879.

It is an arithmetic number, because the mean of its divisors is an integer number (10378879).

Almost surely, 2^20757757 is an apocalyptic number.

It is an amenable number.

20757757 is a deficient number, since it is larger than the sum of its proper divisors (1).

20757757 is an equidigital number, since it uses as much as digits as its factorization.

20757757 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 120050, while the sum is 40.

The square root of 20757757 is about 4556.0681513779. The cubic root of 20757757 is about 274.8274708449.

The spelling of 20757757 in words is "twenty million, seven hundred fifty-seven thousand, seven hundred fifty-seven".