2211981 has 4 divisors (see below), whose sum is σ = 2949312. Its totient is φ = 1474652.

The previous prime is 2211977. The next prime is 2211983. The reversal of 2211981 is 1891122.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 2211981 - 2² = 2211977 is a prime.

It is a super-2 number, since 2×2211981² = 9785719888722, which contains 22 as substring.

It is a D-number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2211983) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 368661 + ... + 368666.

It is an arithmetic number, because the mean of its divisors is an integer number (737328).

2^2211981 is an apocalyptic number.

It is an amenable number.

2211981 is a deficient number, since it is larger than the sum of its proper divisors (737331).

2211981 is an equidigital number, since it uses as much as digits as its factorization.

2211981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 737330.

The product of its digits is 288, while the sum is 24.

The square root of 2211981 is about 1487.2730078906. The cubic root of 2211981 is about 130.2948141494.

The spelling of 2211981 in words is "two million, two hundred eleven thousand, nine hundred eighty-one".