1997491 has 4 divisors (see below), whose sum is σ = 2066400. Its totient is φ = 1928584.

The previous prime is 1997473. The next prime is 1997503. The reversal of 1997491 is 1947991.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 1997491 - 2⁵ = 1997459 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1997431) 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, 34411 + ... + 34468.

It is an arithmetic number, because the mean of its divisors is an integer number (516600).

2^1997491 is an apocalyptic number.

1997491 is a deficient number, since it is larger than the sum of its proper divisors (68909).

1997491 is an equidigital number, since it uses as much as digits as its factorization.

1997491 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 68908.

The product of its digits is 20412, while the sum is 40.

The square root of 1997491 is about 1413.3262185356. The cubic root of 1997491 is about 125.9393972441.

The spelling of 1997491 in words is "one million, nine hundred ninety-seven thousand, four hundred ninety-one".