1851997 has 16 divisors (see below), whose sum is σ = 2280960. Its totient is φ = 1467648.

The previous prime is 1851991. The next prime is 1852003. The reversal of 1851997 is 7991581.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (1851991) and next prime (1852003).

It is not a de Polignac number, because 1851997 - 2⁷ = 1851869 is a prime.

It is a Duffinian number.

1851997 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1851991) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9303 + ... + 9499.

It is an arithmetic number, because the mean of its divisors is an integer number (142560).

2^1851997 is an apocalyptic number.

1851997 is a gapful number since it is divisible by the number (17) formed by its first and last digit.

It is an amenable number.

1851997 is a deficient number, since it is larger than the sum of its proper divisors (428963).

1851997 is a wasteful number, since it uses less digits than its factorization.

1851997 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 300.

The product of its digits is 22680, while the sum is 40.

The square root of 1851997 is about 1360.8809646696. The cubic root of 1851997 is about 122.8042582530.

The spelling of 1851997 in words is "one million, eight hundred fifty-one thousand, nine hundred ninety-seven".