136658981 has 4 divisors (see below), whose sum is σ = 136732332. Its totient is φ = 136585632.

The previous prime is 136658957. The next prime is 136658983. The reversal of 136658981 is 189856631.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 112550881 + 24108100 = 10609^2 + 4910^2 .

It is a cyclic number.

It is not a de Polignac number, because 136658981 - 2⁶ = 136658917 is a prime.

It is a super-2 number, since 2×136658981² = 37351354175916722, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (136658983) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 33806 + ... + 37631.

It is an arithmetic number, because the mean of its divisors is an integer number (34183083).

Almost surely, 2^136658981 is an apocalyptic number.

It is an amenable number.

136658981 is a deficient number, since it is larger than the sum of its proper divisors (73351).

136658981 is an equidigital number, since it uses as much as digits as its factorization.

136658981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 73350.

The product of its digits is 311040, while the sum is 47.

The square root of 136658981 is about 11690.1232243292. The cubic root of 136658981 is about 515.0855810270.

The spelling of 136658981 in words is "one hundred thirty-six million, six hundred fifty-eight thousand, nine hundred eighty-one".