136156721 has 2 divisors, whose sum is σ = 136156722. Its totient is φ = 136156720.

The previous prime is 136156703. The next prime is 136156789. The reversal of 136156721 is 127651631.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 90459121 + 45697600 = 9511^2 + 6760^2 .

It is an emirp because it is prime and its reverse (127651631) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 136156721 - 2¹⁴ = 136140337 is a prime.

It is a super-3 number, since 3×136156721³ (a number of 25 digits) contains 333 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (136159721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 68078360 + 68078361.

It is an arithmetic number, because the mean of its divisors is an integer number (68078361).

Almost surely, 2^136156721 is an apocalyptic number.

It is an amenable number.

136156721 is a deficient number, since it is larger than the sum of its proper divisors (1).

136156721 is an equidigital number, since it uses as much as digits as its factorization.

136156721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7560, while the sum is 32.

The square root of 136156721 is about 11668.6212124655. The cubic root of 136156721 is about 514.4537784899.

The spelling of 136156721 in words is "one hundred thirty-six million, one hundred fifty-six thousand, seven hundred twenty-one".