136561891 has 2 divisors, whose sum is σ = 136561892. Its totient is φ = 136561890.

The previous prime is 136561847. The next prime is 136561921. The reversal of 136561891 is 198165631.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 136561891 - 2¹³ = 136553699 is a prime.

It is not a weakly prime, because it can be changed into another prime (136561811) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 68280945 + 68280946.

It is an arithmetic number, because the mean of its divisors is an integer number (68280946).

Almost surely, 2^136561891 is an apocalyptic number.

136561891 is a deficient number, since it is larger than the sum of its proper divisors (1).

136561891 is an equidigital number, since it uses as much as digits as its factorization.

136561891 is an evil number, because the sum of its binary digits is even.

The product of its digits is 38880, while the sum is 40.

The square root of 136561891 is about 11685.9698356619. The cubic root of 136561891 is about 514.9635704900.

The spelling of 136561891 in words is "one hundred thirty-six million, five hundred sixty-one thousand, eight hundred ninety-one".