20615131 has 4 divisors (see below), whose sum is σ = 20964600. Its totient is φ = 20265664.

The previous prime is 20615117. The next prime is 20615149. The reversal of 20615131 is 13151602.

20615131 is nontrivially palindromic in base 15.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 20615131 - 2⁹ = 20614619 is a prime.

It is a super-2 number, since 2×20615131² = 849967252294322, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20615099 and 20615108.

It is not an unprimeable number, because it can be changed into a prime (20615191) 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, 174646 + ... + 174763.

It is an arithmetic number, because the mean of its divisors is an integer number (5241150).

Almost surely, 2^20615131 is an apocalyptic number.

20615131 is a deficient number, since it is larger than the sum of its proper divisors (349469).

20615131 is an equidigital number, since it uses as much as digits as its factorization.

20615131 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 349468.

The product of its (nonzero) digits is 180, while the sum is 19.

The square root of 20615131 is about 4540.3888599987. The cubic root of 20615131 is about 274.1965795879.

Adding to 20615131 its reverse (13151602), we get a palindrome (33766733).

The spelling of 20615131 in words is "twenty million, six hundred fifteen thousand, one hundred thirty-one".