20131215 has 16 divisors (see below), whose sum is σ = 34687968. Its totient is φ = 9910656.

The previous prime is 20131211. The next prime is 20131217. The reversal of 20131215 is 51213102.

It is not a de Polignac number, because 20131215 - 2² = 20131211 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a junction number, because it is equal to n+sod(n) for n = 20131194 and 20131203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20131211) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 51424 + ... + 51813.

It is an arithmetic number, because the mean of its divisors is an integer number (2167998).

Almost surely, 2^20131215 is an apocalyptic number.

20131215 is a deficient number, since it is larger than the sum of its proper divisors (14556753).

20131215 is a wasteful number, since it uses less digits than its factorization.

20131215 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 103258.

The product of its (nonzero) digits is 60, while the sum is 15.

The square root of 20131215 is about 4486.7822545784. The cubic root of 20131215 is about 272.0340886847.

Adding to 20131215 its reverse (51213102), we get a palindrome (71344317).

The spelling of 20131215 in words is "twenty million, one hundred thirty-one thousand, two hundred fifteen".