20121613 has 4 divisors (see below), whose sum is σ = 20405088. Its totient is φ = 19838140.

The previous prime is 20121581. The next prime is 20121623. The reversal of 20121613 is 31612102.

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: 31612102 = 2 ⋅15806051.

It is a cyclic number.

It is not a de Polignac number, because 20121613 - 2⁵ = 20121581 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 (20121623) 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, 141631 + ... + 141772.

It is an arithmetic number, because the mean of its divisors is an integer number (5101272).

Almost surely, 2^20121613 is an apocalyptic number.

It is an amenable number.

20121613 is a deficient number, since it is larger than the sum of its proper divisors (283475).

20121613 is an equidigital number, since it uses as much as digits as its factorization.

20121613 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 283474.

The product of its (nonzero) digits is 72, while the sum is 16.

The square root of 20121613 is about 4485.7120950859. The cubic root of 20121613 is about 271.9908310418.

Adding to 20121613 its reverse (31612102), we get a palindrome (51733715).

The spelling of 20121613 in words is "twenty million, one hundred twenty-one thousand, six hundred thirteen".