136573721 has 8 divisors (see below), whose sum is σ = 138325320. Its totient is φ = 134831872.

The previous prime is 136573709. The next prime is 136573751. The reversal of 136573721 is 127375631.

It can be written as a sum of positive squares in 4 ways, for example, as 3748096 + 132825625 = 1936^2 + 11525^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-136573721 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (136573751) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 28151 + ... + 32643.

It is an arithmetic number, because the mean of its divisors is an integer number (17290665).

Almost surely, 2^136573721 is an apocalyptic number.

It is an amenable number.

136573721 is a deficient number, since it is larger than the sum of its proper divisors (1751599).

136573721 is a wasteful number, since it uses less digits than its factorization.

136573721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4875.

The product of its digits is 26460, while the sum is 35.

The square root of 136573721 is about 11686.4759872256. The cubic root of 136573721 is about 514.9784400438.

The spelling of 136573721 in words is "one hundred thirty-six million, five hundred seventy-three thousand, seven hundred twenty-one".