2157591 has 4 divisors (see below), whose sum is σ = 2876792. Its totient is φ = 1438392.

The previous prime is 2157587. The next prime is 2157641. The reversal of 2157591 is 1957512.

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

It is not a de Polignac number, because 2157591 - 2² = 2157587 is a prime.

It is a D-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 (2157511) 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, 359596 + ... + 359601.

It is an arithmetic number, because the mean of its divisors is an integer number (719198).

2^2157591 is an apocalyptic number.

2157591 is a deficient number, since it is larger than the sum of its proper divisors (719201).

2157591 is an equidigital number, since it uses as much as digits as its factorization.

2157591 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 719200.

The product of its digits is 3150, while the sum is 30.

The square root of 2157591 is about 1468.8740585905. The cubic root of 2157591 is about 129.2180076630.

The spelling of 2157591 in words is "two million, one hundred fifty-seven thousand, five hundred ninety-one".