136421509 has 4 divisors (see below), whose sum is σ = 155910304. Its totient is φ = 116932716.

The previous prime is 136421497. The next prime is 136421521. The reversal of 136421509 is 905124631.

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: 905124631 = 601 ⋅1506031.

It is an interprime number because it is at equal distance from previous prime (136421497) and next prime (136421521).

It is a cyclic number.

It is not a de Polignac number, because 136421509 - 2⁷ = 136421381 is a prime.

It is a super-2 number, since 2×136421509² = 37221656235674162, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (136421599) 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, 9744387 + ... + 9744400.

It is an arithmetic number, because the mean of its divisors is an integer number (38977576).

Almost surely, 2^136421509 is an apocalyptic number.

It is an amenable number.

136421509 is a deficient number, since it is larger than the sum of its proper divisors (19488795).

136421509 is an equidigital number, since it uses as much as digits as its factorization.

136421509 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19488794.

The product of its (nonzero) digits is 6480, while the sum is 31.

The square root of 136421509 is about 11679.9618578144. The cubic root of 136421509 is about 514.7870536964.

It can be divided in two parts, 13642 and 1509, that added together give a palindrome (15151).

The spelling of 136421509 in words is "one hundred thirty-six million, four hundred twenty-one thousand, five hundred nine".