1971791 has 4 divisors (see below), whose sum is σ = 2013792. Its totient is φ = 1929792.

The previous prime is 1971727. The next prime is 1971799.

It is a happy number.

1971791 is nontrivially palindromic in base 10.

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 1971791 - 2⁶ = 1971727 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1971799) 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, 20930 + ... + 21023.

It is an arithmetic number, because the mean of its divisors is an integer number (503448).

2^1971791 is an apocalyptic number.

1971791 is a deficient number, since it is larger than the sum of its proper divisors (42001).

1971791 is an equidigital number, since it uses as much as digits as its factorization.

1971791 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42000.

The product of its digits is 3969, while the sum is 35.

The square root of 1971791 is about 1404.2047571490. The cubic root of 1971791 is about 125.3969461358.

The spelling of 1971791 in words is "one million, nine hundred seventy-one thousand, seven hundred ninety-one".