19926237781 has 2 divisors, whose sum is σ = 19926237782. Its totient is φ = 19926237780.

The previous prime is 19926237769. The next prime is 19926237791. The reversal of 19926237781 is 18773262991.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19379145681 + 547092100 = 139209^2 + 23390^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-19926237781 is a prime.

It is a super-2 number, since 2×19926237781² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19926237701) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9963118890 + 9963118891.

It is an arithmetic number, because the mean of its divisors is an integer number (9963118891).

Almost surely, 2^19926237781 is an apocalyptic number.

It is an amenable number.

19926237781 is a deficient number, since it is larger than the sum of its proper divisors (1).

19926237781 is an equidigital number, since it uses as much as digits as its factorization.

19926237781 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2286144, while the sum is 55.

The spelling of 19926237781 in words is "nineteen billion, nine hundred twenty-six million, two hundred thirty-seven thousand, seven hundred eighty-one".