1661172 has 36 divisors (see below), whose sum is σ = 4126080. Its totient is φ = 520064.

The previous prime is 1661161. The next prime is 1661173. The reversal of 1661172 is 2711661.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1661173) 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, 3229 + ... + 3707.

2^1661172 is an apocalyptic number.

1661172 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 1661172, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2063040).

1661172 is an abundant number, since it is smaller than the sum of its proper divisors (2464908).

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

1661172 is a wasteful number, since it uses less digits than its factorization.

1661172 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 520 (or 501 counting only the distinct ones).

The product of its digits is 504, while the sum is 24.

The square root of 1661172 is about 1288.8646166297. The cubic root of 1661172 is about 118.4326737497.

The spelling of 1661172 in words is "one million, six hundred sixty-one thousand, one hundred seventy-two".