136221391 has 8 divisors (see below), whose sum is σ = 144993024. Its totient is φ = 127534080.

The previous prime is 136221301. The next prime is 136221401. The reversal of 136221391 is 193122631.

136221391 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a cyclic number.

It is not a de Polignac number, because 136221391 - 2²⁷ = 2003663 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 (136221301) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 17730 + ... + 24223.

It is an arithmetic number, because the mean of its divisors is an integer number (18124128).

Almost surely, 2^136221391 is an apocalyptic number.

136221391 is a deficient number, since it is larger than the sum of its proper divisors (8771633).

136221391 is a wasteful number, since it uses less digits than its factorization.

136221391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42161.

The product of its digits is 1944, while the sum is 28.

The square root of 136221391 is about 11671.3919906753. The cubic root of 136221391 is about 514.5352151845.

The spelling of 136221391 in words is "one hundred thirty-six million, two hundred twenty-one thousand, three hundred ninety-one".