12920542781 has 2 divisors, whose sum is σ = 12920542782. Its totient is φ = 12920542780.

The previous prime is 12920542751. The next prime is 12920542787. The reversal of 12920542781 is 18724502921.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 6534135556 + 6386407225 = 80834^2 + 79915^2 .

It is a cyclic number.

It is not a de Polignac number, because 12920542781 - 2¹⁰ = 12920541757 is a prime.

It is a super-2 number, since 2×12920542781² (a number of 21 digits) contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (12920542787) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6460271390 + 6460271391.

It is an arithmetic number, because the mean of its divisors is an integer number (6460271391).

Almost surely, 2^12920542781 is an apocalyptic number.

It is an amenable number.

12920542781 is a deficient number, since it is larger than the sum of its proper divisors (1).

12920542781 is an equidigital number, since it uses as much as digits as its factorization.

12920542781 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 80640, while the sum is 41.

The spelling of 12920542781 in words is "twelve billion, nine hundred twenty million, five hundred forty-two thousand, seven hundred eighty-one".