2191901 has 8 divisors (see below), whose sum is σ = 2265144. Its totient is φ = 2119680.

The previous prime is 2191883. The next prime is 2191949. The reversal of 2191901 is 1091912.

It can be written as a sum of positive squares in 4 ways, for example, as 89401 + 2102500 = 299^2 + 1450^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2191901 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2191951) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7775 + ... + 8051.

It is an arithmetic number, because the mean of its divisors is an integer number (283143).

2^2191901 is an apocalyptic number.

It is an amenable number.

2191901 is a deficient number, since it is larger than the sum of its proper divisors (73243).

2191901 is a wasteful number, since it uses less digits than its factorization.

2191901 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 511.

The product of its (nonzero) digits is 162, while the sum is 23.

The square root of 2191901 is about 1480.5070077511. The cubic root of 2191901 is about 129.8993501018.

The spelling of 2191901 in words is "two million, one hundred ninety-one thousand, nine hundred one".