136686639221 has 4 divisors (see below), whose sum is σ = 149112697344. Its totient is φ = 124260581100.

The previous prime is 136686639209. The next prime is 136686639247. The reversal of 136686639221 is 122936686631.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 122936686631 = 11 ⋅11176062421.

It is a cyclic number.

It is not a de Polignac number, because 136686639221 - 2¹⁸ = 136686377077 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 (136686639251) 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, 6213029045 + ... + 6213029066.

It is an arithmetic number, because the mean of its divisors is an integer number (37278174336).

Almost surely, 2^136686639221 is an apocalyptic number.

136686639221 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

136686639221 is a deficient number, since it is larger than the sum of its proper divisors (12426058123).

136686639221 is a wasteful number, since it uses less digits than its factorization.

136686639221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12426058122.

The product of its digits is 3359232, while the sum is 53.

The spelling of 136686639221 in words is "one hundred thirty-six billion, six hundred eighty-six million, six hundred thirty-nine thousand, two hundred twenty-one".