1997172 has 36 divisors (see below), whose sum is σ = 5225220. Its totient is φ = 642432.

The previous prime is 1997161. The next prime is 1997173. The reversal of 1997172 is 2717991.

It can be written as a sum of positive squares in 2 ways, for example, as 1425636 + 571536 = 1194^2 + 756^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1997173) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 88 + ... + 2000.

It is an arithmetic number, because the mean of its divisors is an integer number (145145).

2^1997172 is an apocalyptic number.

1997172 is a gapful number since it is divisible by the number (12) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1997172, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2612610).

1997172 is an abundant number, since it is smaller than the sum of its proper divisors (3228048).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1997172 is a wasteful number, since it uses less digits than its factorization.

1997172 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1952 (or 1947 counting only the distinct ones).

The product of its digits is 7938, while the sum is 36.

The square root of 1997172 is about 1413.2133596878. The cubic root of 1997172 is about 125.9326926989.

The spelling of 1997172 in words is "one million, nine hundred ninety-seven thousand, one hundred seventy-two".