2001239857 has 4 divisors (see below), whose sum is σ = 2002420836. Its totient is φ = 2000058880.

The previous prime is 2001239843. The next prime is 2001239861. The reversal of 2001239857 is 7589321002.

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 1952225856 + 49014001 = 44184^2 + 7001^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2001239857 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2001239827) 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, 587944 + ... + 591337.

It is an arithmetic number, because the mean of its divisors is an integer number (500605209).

Almost surely, 2^2001239857 is an apocalyptic number.

It is an amenable number.

2001239857 is a deficient number, since it is larger than the sum of its proper divisors (1180979).

2001239857 is a wasteful number, since it uses less digits than its factorization.

2001239857 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1180978.

The product of its (nonzero) digits is 30240, while the sum is 37.

The square root of 2001239857 is about 44735.2194249676. The cubic root of 2001239857 is about 1260.1813497687.

The spelling of 2001239857 in words is "two billion, one million, two hundred thirty-nine thousand, eight hundred fifty-seven".