2151861 has 8 divisors (see below), whose sum is σ = 2881344. Its totient is φ = 1428480.

The previous prime is 2151847. The next prime is 2151869. The reversal of 2151861 is 1681512.

2151861 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is not a de Polignac number, because 2151861 - 2⁹ = 2151349 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2151869) 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 7 ways as a sum of consecutive naturals, for example, 625 + ... + 2166.

It is an arithmetic number, because the mean of its divisors is an integer number (360168).

2^2151861 is an apocalyptic number.

It is an amenable number.

2151861 is a deficient number, since it is larger than the sum of its proper divisors (729483).

2151861 is a wasteful number, since it uses less digits than its factorization.

2151861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3051.

The product of its digits is 480, while the sum is 24.

The square root of 2151861 is about 1466.9222883302. The cubic root of 2151861 is about 129.1035164540.

The spelling of 2151861 in words is "two million, one hundred fifty-one thousand, eight hundred sixty-one".