2191913 has 4 divisors (see below), whose sum is σ = 2227908. Its totient is φ = 2155920.

The previous prime is 2191883. The next prime is 2191949. The reversal of 2191913 is 3191912.

2191913 = T₂₃₇ + T₂₃₈ + ... + T₂₉₇.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 683929 + 1507984 = 827^2 + 1228^2 .

It is a cyclic number.

It is not a de Polignac number, because 2191913 - 2¹² = 2187817 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2191993) 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, 17906 + ... + 18027.

It is an arithmetic number, because the mean of its divisors is an integer number (556977).

2^2191913 is an apocalyptic number.

It is an amenable number.

2191913 is a deficient number, since it is larger than the sum of its proper divisors (35995).

2191913 is an equidigital number, since it uses as much as digits as its factorization.

2191913 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35994.

The product of its digits is 486, while the sum is 26.

The square root of 2191913 is about 1480.5110604112. The cubic root of 2191913 is about 129.8995871547.

Subtracting 2191913 from its reverse (3191912), we obtain a palindrome (999999).

The spelling of 2191913 in words is "two million, one hundred ninety-one thousand, nine hundred thirteen".