1997857 has 12 divisors (see below), whose sum is σ = 2200576. Its totient is φ = 1811520.

The previous prime is 1997851. The next prime is 1997867. The reversal of 1997857 is 7587991.

It is not a de Polignac number, because 1997857 - 2¹⁹ = 1473569 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1997851) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 8848 + ... + 9070.

2^1997857 is an apocalyptic number.

1997857 is a gapful number since it is divisible by the number (17) formed by its first and last digit.

It is an amenable number.

1997857 is a deficient number, since it is larger than the sum of its proper divisors (202719).

1997857 is a wasteful number, since it uses less digits than its factorization.

1997857 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 288 (or 271 counting only the distinct ones).

The product of its digits is 158760, while the sum is 46.

The square root of 1997857 is about 1413.4556943888. The cubic root of 1997857 is about 125.9470887272.

The spelling of 1997857 in words is "one million, nine hundred ninety-seven thousand, eight hundred fifty-seven".