2191801 has 4 divisors (see below), whose sum is σ = 2213604. Its totient is φ = 2170000.

The previous prime is 2191799. The next prime is 2191807. The reversal of 2191801 is 1081912.

2191801 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 2027776 + 164025 = 1424^2 + 405^2 .

It is a cyclic number.

It is not a de Polignac number, because 2191801 - 2¹ = 2191799 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2191807) 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 3 ways as a sum of consecutive naturals, for example, 10750 + ... + 10951.

It is an arithmetic number, because the mean of its divisors is an integer number (553401).

2^2191801 is an apocalyptic number.

It is an amenable number.

2191801 is a deficient number, since it is larger than the sum of its proper divisors (21803).

2191801 is a wasteful number, since it uses less digits than its factorization.

2191801 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21802.

The product of its (nonzero) digits is 144, while the sum is 22.

The square root of 2191801 is about 1480.4732351515. The cubic root of 2191801 is about 129.8973746275.

It can be divided in two parts, 2191 and 801, that added together give a palindrome (2992).

The spelling of 2191801 in words is "two million, one hundred ninety-one thousand, eight hundred one".