20513015 has 4 divisors (see below), whose sum is σ = 24615624. Its totient is φ = 16410408.

The previous prime is 20513011. The next prime is 20513029. The reversal of 20513015 is 51031502.

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 20513015 - 2² = 20513011 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20512984 and 20513002.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20513011) 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, 2051297 + ... + 2051306.

It is an arithmetic number, because the mean of its divisors is an integer number (6153906).

Almost surely, 2^20513015 is an apocalyptic number.

20513015 is a deficient number, since it is larger than the sum of its proper divisors (4102609).

20513015 is an equidigital number, since it uses as much as digits as its factorization.

20513015 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4102608.

The product of its (nonzero) digits is 150, while the sum is 17.

The square root of 20513015 is about 4529.1296073308. The cubic root of 20513015 is about 273.7430903922.

Adding to 20513015 its reverse (51031502), we get a palindrome (71544517).

The spelling of 20513015 in words is "twenty million, five hundred thirteen thousand, fifteen".