136639861 has 2 divisors, whose sum is σ = 136639862. Its totient is φ = 136639860.

The previous prime is 136639859. The next prime is 136639879. The reversal of 136639861 is 168936631.

136639861 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 101888836 + 34751025 = 10094^2 + 5895^2 .

It is a cyclic number.

It is not a de Polignac number, because 136639861 - 2¹ = 136639859 is a prime.

It is a super-2 number, since 2×136639861² = 37340903228198642, which contains 22 as substring.

Together with 136639859, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (136639891) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 68319930 + 68319931.

It is an arithmetic number, because the mean of its divisors is an integer number (68319931).

Almost surely, 2^136639861 is an apocalyptic number.

It is an amenable number.

136639861 is a deficient number, since it is larger than the sum of its proper divisors (1).

136639861 is an equidigital number, since it uses as much as digits as its factorization.

136639861 is an evil number, because the sum of its binary digits is even.

The product of its digits is 139968, while the sum is 43.

The square root of 136639861 is about 11689.3054113579. The cubic root of 136639861 is about 515.0615579793.

The spelling of 136639861 in words is "one hundred thirty-six million, six hundred thirty-nine thousand, eight hundred sixty-one".