136873921 has 2 divisors, whose sum is σ = 136873922. Its totient is φ = 136873920.

The previous prime is 136873837. The next prime is 136873937. The reversal of 136873921 is 129378631.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 120560400 + 16313521 = 10980^2 + 4039^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-136873921 is a prime.

It is not a weakly prime, because it can be changed into another prime (136873951) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 68436960 + 68436961.

It is an arithmetic number, because the mean of its divisors is an integer number (68436961).

Almost surely, 2^136873921 is an apocalyptic number.

It is an amenable number.

136873921 is a deficient number, since it is larger than the sum of its proper divisors (1).

136873921 is an equidigital number, since it uses as much as digits as its factorization.

136873921 is an evil number, because the sum of its binary digits is even.

The product of its digits is 54432, while the sum is 40.

The square root of 136873921 is about 11699.3128430690. The cubic root of 136873921 is about 515.3554852343.

The spelling of 136873921 in words is "one hundred thirty-six million, eight hundred seventy-three thousand, nine hundred twenty-one".