136910021 has 4 divisors (see below), whose sum is σ = 136936044. Its totient is φ = 136884000.

The previous prime is 136910017. The next prime is 136910041. The reversal of 136910021 is 120019631.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 120019631 = 31 ⋅3871601.

It can be written as a sum of positive squares in 2 ways, for example, as 6630625 + 130279396 = 2575^2 + 11414^2 .

It is a cyclic number.

It is not a de Polignac number, because 136910021 - 2² = 136910017 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (136910041) 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, 2030 + ... + 16671.

It is an arithmetic number, because the mean of its divisors is an integer number (34234011).

Almost surely, 2^136910021 is an apocalyptic number.

It is an amenable number.

136910021 is a deficient number, since it is larger than the sum of its proper divisors (26023).

136910021 is an equidigital number, since it uses as much as digits as its factorization.

136910021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26022.

The product of its (nonzero) digits is 324, while the sum is 23.

The square root of 136910021 is about 11700.8555670088. The cubic root of 136910021 is about 515.4007889647.

Adding to 136910021 its reverse (120019631), we get a palindrome (256929652).

The spelling of 136910021 in words is "one hundred thirty-six million, nine hundred ten thousand, twenty-one".