20715 has 8 divisors (see below), whose sum is σ = 33168. Its totient is φ = 11040.

The previous prime is 20707. The next prime is 20717. The reversal of 20715 is 51702.

It is a happy number.

20715 is digitally balanced in base 4, 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 not a de Polignac number, because 20715 - 2³ = 20707 is a prime.

It is a super-2 number, since 2×20715² = 858222450, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (15), and also a Moran number because the ratio is a prime number: 1381 = 20715 / (2 + 0 + 7 + 1 + 5).

It is a plaindrome in base 14.

It is a nialpdrome in base 12 and base 15.

It is a zygodrome in base 14.

It is a junction number, because it is equal to n+sod(n) for n = 20694 and 20703.

It is not an unprimeable number, because it can be changed into a prime (20717) 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, 676 + ... + 705.

It is an arithmetic number, because the mean of its divisors is an integer number (4146).

2²⁰⁷¹⁵ is an apocalyptic number.

20715 is a deficient number, since it is larger than the sum of its proper divisors (12453).

20715 is a wasteful number, since it uses less digits than its factorization.

20715 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1389.

The product of its (nonzero) digits is 70, while the sum is 15.

The square root of 20715 is about 143.9270648627. The cubic root of 20715 is about 27.4638643835.

It can be divided in two parts, 207 and 15, that added together give a palindrome (222).

The spelling of 20715 in words is "twenty thousand, seven hundred fifteen".