2197661 has 4 divisors (see below), whose sum is σ = 2200992. Its totient is φ = 2194332.

The previous prime is 2197651. The next prime is 2197681. The reversal of 2197661 is 1667912.

It is a happy number.

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 2197661 - 2¹⁸ = 1935517 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2197631) 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, 305 + ... + 2118.

It is an arithmetic number, because the mean of its divisors is an integer number (550248).

2^2197661 is an apocalyptic number.

It is an amenable number.

2197661 is a deficient number, since it is larger than the sum of its proper divisors (3331).

2197661 is an equidigital number, since it uses as much as digits as its factorization.

2197661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3330.

The product of its digits is 4536, while the sum is 32.

The square root of 2197661 is about 1482.4510109950. The cubic root of 2197661 is about 130.0130361681.

The spelling of 2197661 in words is "two million, one hundred ninety-seven thousand, six hundred sixty-one".