2121864 has 16 divisors (see below), whose sum is σ = 5304720. Its totient is φ = 707280.

The previous prime is 2121853. The next prime is 2121869. The reversal of 2121864 is 4681212.

It is a Harshad number since it is a multiple of its sum of digits (24), and also a Moran number because the ratio is a prime number: 88411 = 2121864 / (2 + 1 + 2 + 1 + 8 + 6 + 4).

It is a nude number because it is divisible by every one of its digits.

It is a d-powerful number, because it can be written as 2⁷ + 1 + 2¹³ + 1 + 8⁷ + 6 + 4⁷ .

It is not an unprimeable number, because it can be changed into a prime (2121869) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 44182 + ... + 44229.

It is an arithmetic number, because the mean of its divisors is an integer number (331545).

2^2121864 is an apocalyptic number.

2121864 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

2121864 is an abundant number, since it is smaller than the sum of its proper divisors (3182856).

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

2121864 is a wasteful number, since it uses less digits than its factorization.

2121864 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 88420 (or 88416 counting only the distinct ones).

The product of its digits is 768, while the sum is 24.

The square root of 2121864 is about 1456.6619374446. The cubic root of 2121864 is about 128.5008049529.

The spelling of 2121864 in words is "two million, one hundred twenty-one thousand, eight hundred sixty-four".