61787183981 has 2 divisors, whose sum is σ = 61787183982. Its totient is φ = 61787183980.

The previous prime is 61787183971. The next prime is 61787184031. The reversal of 61787183981 is 18938178716.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 55162037956 + 6625146025 = 234866^2 + 81395^2 .

It is a cyclic number.

It is not a de Polignac number, because 61787183981 - 2¹⁴ = 61787167597 is a prime.

It is a super-2 number, since 2×61787183981² (a number of 22 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 61787183981.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (61787183911) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30893591990 + 30893591991.

It is an arithmetic number, because the mean of its divisors is an integer number (30893591991).

Almost surely, 2^61787183981 is an apocalyptic number.

It is an amenable number.

61787183981 is a deficient number, since it is larger than the sum of its proper divisors (1).

61787183981 is an equidigital number, since it uses as much as digits as its factorization.

61787183981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4064256, while the sum is 59.

The spelling of 61787183981 in words is "sixty-one billion, seven hundred eighty-seven million, one hundred eighty-three thousand, nine hundred eighty-one".