123699581 has 2 divisors, whose sum is σ = 123699582. Its totient is φ = 123699580.

The previous prime is 123699551. The next prime is 123699647. The reversal of 123699581 is 185996321.

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., 122456356 + 1243225 = 11066^2 + 1115^2 .

It is a cyclic number.

It is not a de Polignac number, because 123699581 - 2¹⁰ = 123698557 is a prime.

It is a super-2 number, since 2×123699581² = 30603172679151122, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (123699551) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 61849790 + 61849791.

It is an arithmetic number, because the mean of its divisors is an integer number (61849791).

Almost surely, 2^123699581 is an apocalyptic number.

It is an amenable number.

123699581 is a deficient number, since it is larger than the sum of its proper divisors (1).

123699581 is an equidigital number, since it uses as much as digits as its factorization.

123699581 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 116640, while the sum is 44.

The square root of 123699581 is about 11122.0313342483. The cubic root of 123699581 is about 498.2600602426.

The spelling of 123699581 in words is "one hundred twenty-three million, six hundred ninety-nine thousand, five hundred eighty-one".