2101815 has 16 divisors (see below), whose sum is σ = 3736800. Its totient is φ = 1120896.

The previous prime is 2101811. The next prime is 2101817. The reversal of 2101815 is 5181012.

It is not a de Polignac number, because 2101815 - 2² = 2101811 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2101811) 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, 7650 + ... + 7919.

It is an arithmetic number, because the mean of its divisors is an integer number (233550).

2^2101815 is an apocalyptic number.

2101815 is a deficient number, since it is larger than the sum of its proper divisors (1634985).

2101815 is a wasteful number, since it uses less digits than its factorization.

2101815 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15583 (or 15577 counting only the distinct ones).

The product of its (nonzero) digits is 80, while the sum is 18.

The square root of 2101815 is about 1449.7637738611. The cubic root of 2101815 is about 128.0947987511.

Adding to 2101815 its reverse (5181012), we get a palindrome (7282827).

It can be divided in two parts, 2101 and 815, that added together give a square (2916 = 54²).

The spelling of 2101815 in words is "two million, one hundred one thousand, eight hundred fifteen".