20415 has 8 divisors (see below), whose sum is σ = 32688. Its totient is φ = 10880.

The previous prime is 20411. The next prime is 20431. The reversal of 20415 is 51402.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 20415 - 2² = 20411 is a prime.

It is a nialpdrome in base 12.

It is a self number, because there is not a number n which added to its sum of digits gives 20415.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 20415.

It is not an unprimeable number, because it can be changed into a prime (20411) 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, 666 + ... + 695.

It is an arithmetic number, because the mean of its divisors is an integer number (4086).

2²⁰⁴¹⁵ is an apocalyptic number.

20415 is a deficient number, since it is larger than the sum of its proper divisors (12273).

20415 is a wasteful number, since it uses less digits than its factorization.

20415 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1369.

The product of its (nonzero) digits is 40, while the sum is 12.

The square root of 20415 is about 142.8810694249. The cubic root of 20415 is about 27.3306395653.

Adding to 20415 its reverse (51402), we get a palindrome (71817).

It can be divided in two parts, 20 and 415, that added together give a triangular number (435 = T₂₉).

The spelling of 20415 in words is "twenty thousand, four hundred fifteen".