2100391 has 4 divisors (see below), whose sum is σ = 2106792. Its totient is φ = 2093992.

The previous prime is 2100377. The next prime is 2100403. The reversal of 2100391 is 1930012.

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 2100391 - 2¹⁵ = 2067623 is a prime.

It is a Duffinian number.

2100391 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2100191) 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, 2680 + ... + 3373.

It is an arithmetic number, because the mean of its divisors is an integer number (526698).

2^2100391 is an apocalyptic number.

2100391 is a deficient number, since it is larger than the sum of its proper divisors (6401).

2100391 is an equidigital number, since it uses as much as digits as its factorization.

2100391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6400.

The product of its (nonzero) digits is 54, while the sum is 16.

The square root of 2100391 is about 1449.2725761567. The cubic root of 2100391 is about 128.0658637270.

The spelling of 2100391 in words is "two million, one hundred thousand, three hundred ninety-one".