2171861 has 8 divisors (see below), whose sum is σ = 2225664. Its totient is φ = 2118880.

The previous prime is 2171857. The next prime is 2171881. The reversal of 2171861 is 1681712.

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

It is a cyclic number.

It is not a de Polignac number, because 2171861 - 2² = 2171857 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 2171861.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2171831) 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, 11276 + ... + 11466.

It is an arithmetic number, because the mean of its divisors is an integer number (278208).

2^2171861 is an apocalyptic number.

It is an amenable number.

2171861 is a deficient number, since it is larger than the sum of its proper divisors (53803).

2171861 is a wasteful number, since it uses less digits than its factorization.

2171861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 411.

The product of its digits is 672, while the sum is 26.

The square root of 2171861 is about 1473.7235154533. The cubic root of 2171861 is about 129.5022584243.

The spelling of 2171861 in words is "two million, one hundred seventy-one thousand, eight hundred sixty-one".