1821372 has 24 divisors (see below), whose sum is σ = 4857216. Its totient is φ = 520368.

The previous prime is 1821371. The next prime is 1821373. The reversal of 1821372 is 2731281.

Added to its reverse (2731281) it gives a triangular number (4552653 = T₃₀₁₇).

It is an interprime number because it is at equal distance from previous prime (1821371) and next prime (1821373).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1821371) 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 7 ways as a sum of consecutive naturals, for example, 10758 + ... + 10925.

It is an arithmetic number, because the mean of its divisors is an integer number (202384).

2^1821372 is an apocalyptic number.

1821372 is a gapful number since it is divisible by the number (12) formed by its first and last digit.

It is an amenable number.

1821372 is an abundant number, since it is smaller than the sum of its proper divisors (3035844).

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

1821372 is a wasteful number, since it uses less digits than its factorization.

1821372 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21697 (or 21695 counting only the distinct ones).

The product of its digits is 672, while the sum is 24.

The square root of 1821372 is about 1349.5821575584. The cubic root of 1821372 is about 122.1235870268.

Adding to 1821372 its reverse (2731281), we get a triangular number (4552653 = T₃₀₁₇).

Subtracting 1821372 from its reverse (2731281), we obtain a palindrome (909909).

The spelling of 1821372 in words is "one million, eight hundred twenty-one thousand, three hundred seventy-two".