2117691 has 16 divisors (see below), whose sum is σ = 3215520. Its totient is φ = 1376640.

The previous prime is 2117677. The next prime is 2117699. The reversal of 2117691 is 1967112.

It is not a de Polignac number, because 2117691 - 2⁹ = 2117179 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

2117691 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (2117699) 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, 151 + ... + 2063.

It is an arithmetic number, because the mean of its divisors is an integer number (200970).

2^2117691 is an apocalyptic number.

2117691 is a deficient number, since it is larger than the sum of its proper divisors (1097829).

2117691 is a wasteful number, since it uses less digits than its factorization.

2117691 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1963 (or 1957 counting only the distinct ones).

The product of its digits is 756, while the sum is 27.

The square root of 2117691 is about 1455.2288479823. The cubic root of 2117691 is about 128.4165102361.

The spelling of 2117691 in words is "two million, one hundred seventeen thousand, six hundred ninety-one".