20157102607781 has 2 divisors, whose sum is σ = 20157102607782. Its totient is φ = 20157102607780.

The previous prime is 20157102607753. The next prime is 20157102607783. The reversal of 20157102607781 is 18770620175102.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14220131779681 + 5936970828100 = 3770959^2 + 2436590^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20157102607781 is a prime.

It is a super-2 number, since 2×20157102607781² (a number of 27 digits) contains 22 as substring.

Together with 20157102607783, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20157102607783) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10078551303890 + 10078551303891.

It is an arithmetic number, because the mean of its divisors is an integer number (10078551303891).

Almost surely, 2^{20157102607781} is an apocalyptic number.

It is an amenable number.

20157102607781 is a deficient number, since it is larger than the sum of its proper divisors (1).

20157102607781 is an equidigital number, since it uses as much as digits as its factorization.

20157102607781 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 329280, while the sum is 47.

The spelling of 20157102607781 in words is "twenty trillion, one hundred fifty-seven billion, one hundred two million, six hundred seven thousand, seven hundred eighty-one".