12220187778581 has 2 divisors, whose sum is σ = 12220187778582. Its totient is φ = 12220187778580.

The previous prime is 12220187778577. The next prime is 12220187778629. The reversal of 12220187778581 is 18587778102221.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12207092638225 + 13095140356 = 3493865^2 + 114434^2 .

It is a cyclic number.

It is not a de Polignac number, because 12220187778581 - 2² = 12220187778577 is a prime.

It is a super-3 number, since 3×12220187778581³ (a number of 40 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a self number, because there is not a number n which added to its sum of digits gives 12220187778581.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (12220187778511) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6110093889290 + 6110093889291.

It is an arithmetic number, because the mean of its divisors is an integer number (6110093889291).

Almost surely, 2^{12220187778581} is an apocalyptic number.

It is an amenable number.

12220187778581 is a deficient number, since it is larger than the sum of its proper divisors (1).

12220187778581 is an equidigital number, since it uses as much as digits as its factorization.

12220187778581 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 7024640, while the sum is 59.

The spelling of 12220187778581 in words is "twelve trillion, two hundred twenty billion, one hundred eighty-seven million, seven hundred seventy-eight thousand, five hundred eighty-one".