1811972 has 12 divisors (see below), whose sum is σ = 3183180. Its totient is φ = 902496.

The previous prime is 1811959. The next prime is 1811983. The reversal of 1811972 is 2791181.

It can be written as a sum of positive squares in 2 ways, for example, as 111556 + 1700416 = 334^2 + 1304^2 .

It is a hoax number, since the sum of its digits (29) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 554 + ... + 1982.

It is an arithmetic number, because the mean of its divisors is an integer number (265265).

2^1811972 is an apocalyptic number.

It is an amenable number.

1811972 is a deficient number, since it is larger than the sum of its proper divisors (1371208).

1811972 is a wasteful number, since it uses less digits than its factorization.

1811972 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1750 (or 1748 counting only the distinct ones).

The product of its digits is 1008, while the sum is 29.

The square root of 1811972 is about 1346.0950932234. The cubic root of 1811972 is about 121.9131335416.

It can be divided in two parts, 18 and 11972, that multiplied together give a triangular number (215496 = T₆₅₆).

The spelling of 1811972 in words is "one million, eight hundred eleven thousand, nine hundred seventy-two".