12021252781 has 2 divisors, whose sum is σ = 12021252782. Its totient is φ = 12021252780.

The previous prime is 12021252743. The next prime is 12021252809. The reversal of 12021252781 is 18725212021.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 7007196681 + 5014056100 = 83709^2 + 70810^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-12021252781 is a prime.

It is a super-2 number, since 2×12021252781² (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 (12021252281) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6010626390 + 6010626391.

It is an arithmetic number, because the mean of its divisors is an integer number (6010626391).

Almost surely, 2^12021252781 is an apocalyptic number.

It is an amenable number.

12021252781 is a deficient number, since it is larger than the sum of its proper divisors (1).

12021252781 is an equidigital number, since it uses as much as digits as its factorization.

12021252781 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4480, while the sum is 31.

The spelling of 12021252781 in words is "twelve billion, twenty-one million, two hundred fifty-two thousand, seven hundred eighty-one".