2001571691 has 4 divisors (see below), whose sum is σ = 2287510512. Its totient is φ = 1715632872.

The previous prime is 2001571681. The next prime is 2001571709. The reversal of 2001571691 is 1961751002.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2001571691 is a prime.

It is not an unprimeable number, because it can be changed into a prime (2001571681) 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, 142969400 + ... + 142969413.

It is an arithmetic number, because the mean of its divisors is an integer number (571877628).

Almost surely, 2^2001571691 is an apocalyptic number.

2001571691 is a deficient number, since it is larger than the sum of its proper divisors (285938821).

2001571691 is an equidigital number, since it uses as much as digits as its factorization.

2001571691 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 285938820.

The product of its (nonzero) digits is 3780, while the sum is 32.

The square root of 2001571691 is about 44738.9281387027. The cubic root of 2001571691 is about 1260.2509979097.

The spelling of 2001571691 in words is "two billion, one million, five hundred seventy-one thousand, six hundred ninety-one".