185638385861 has 2 divisors, whose sum is σ = 185638385862. Its totient is φ = 185638385860.

The previous prime is 185638385773. The next prime is 185638385873. The reversal of 185638385861 is 168583836581.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 121170129025 + 64468256836 = 348095^2 + 253906^2 .

It is an emirp because it is prime and its reverse (168583836581) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 185638385861 - 2¹⁰ = 185638384837 is a prime.

It is a super-2 number, since 2×185638385861² (a number of 23 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 185638385794 and 185638385803.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (185638385761) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 92819192930 + 92819192931.

It is an arithmetic number, because the mean of its divisors is an integer number (92819192931).

Almost surely, 2^185638385861 is an apocalyptic number.

It is an amenable number.

185638385861 is a deficient number, since it is larger than the sum of its proper divisors (1).

185638385861 is an equidigital number, since it uses as much as digits as its factorization.

185638385861 is an evil number, because the sum of its binary digits is even.

The product of its digits is 33177600, while the sum is 62.

The spelling of 185638385861 in words is "one hundred eighty-five billion, six hundred thirty-eight million, three hundred eighty-five thousand, eight hundred sixty-one".