181615749181 has 2 divisors, whose sum is σ = 181615749182. Its totient is φ = 181615749180.

The previous prime is 181615749101. The next prime is 181615749193. The reversal of 181615749181 is 181947516181.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 119778980281 + 61836768900 = 346091^2 + 248670^2 .

It is a cyclic number.

It is not a de Polignac number, because 181615749181 - 2⁹ = 181615748669 is a prime.

It is a super-2 number, since 2×181615749181² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (181615749101) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 90807874590 + 90807874591.

It is an arithmetic number, because the mean of its divisors is an integer number (90807874591).

Almost surely, 2^181615749181 is an apocalyptic number.

It is an amenable number.

181615749181 is a deficient number, since it is larger than the sum of its proper divisors (1).

181615749181 is an equidigital number, since it uses as much as digits as its factorization.

181615749181 is an evil number, because the sum of its binary digits is even.

The product of its digits is 483840, while the sum is 52.

The spelling of 181615749181 in words is "one hundred eighty-one billion, six hundred fifteen million, seven hundred forty-nine thousand, one hundred eighty-one".