2181972 has 48 divisors (see below), whose sum is σ = 5588352. Its totient is φ = 658560.

The previous prime is 2181953. The next prime is 2181973. The reversal of 2181972 is 2791812.

2181972 is digitally balanced in base 5, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×2181972² = 9522003617568, which contains 22 as substring.

Its product of digits (2016) is a multiple of the sum of its prime factors (288).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2181973) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10978 + ... + 11174.

It is an arithmetic number, because the mean of its divisors is an integer number (116424).

2^2181972 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 2181972, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2794176).

2181972 is an abundant number, since it is smaller than the sum of its proper divisors (3406380).

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

2181972 is a wasteful number, since it uses less digits than its factorization.

2181972 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 288 (or 286 counting only the distinct ones).

The product of its digits is 2016, while the sum is 30.

The square root of 2181972 is about 1477.1499585350. The cubic root of 2181972 is about 129.7029113248.

The spelling of 2181972 in words is "two million, one hundred eighty-one thousand, nine hundred seventy-two".