20778742297 has 2 divisors, whose sum is σ = 20778742298. Its totient is φ = 20778742296.

The previous prime is 20778742249. The next prime is 20778742333. The reversal of 20778742297 is 79224787702.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14622613776 + 6156128521 = 120924^2 + 78461^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20778742297 is a prime.

It is a super-2 number, since 2×20778742297² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (20778742097) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10389371148 + 10389371149.

It is an arithmetic number, because the mean of its divisors is an integer number (10389371149).

Almost surely, 2^20778742297 is an apocalyptic number.

It is an amenable number.

20778742297 is a deficient number, since it is larger than the sum of its proper divisors (1).

20778742297 is an equidigital number, since it uses as much as digits as its factorization.

20778742297 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5531904, while the sum is 55.

The spelling of 20778742297 in words is "twenty billion, seven hundred seventy-eight million, seven hundred forty-two thousand, two hundred ninety-seven".