2156431 has 4 divisors (see below), whose sum is σ = 2170864. Its totient is φ = 2142000.

The previous prime is 2156417. The next prime is 2156437. The reversal of 2156431 is 1346512.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 2156431 - 2⁷ = 2156303 is a prime.

It is a super-2 number, since 2×2156431² = 9300389315522, which contains 22 as substring.

It is a Duffinian number.

2156431 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2156437) 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, 6990 + ... + 7291.

It is an arithmetic number, because the mean of its divisors is an integer number (542716).

2^2156431 is an apocalyptic number.

2156431 is a deficient number, since it is larger than the sum of its proper divisors (14433).

2156431 is a wasteful number, since it uses less digits than its factorization.

2156431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14432.

The product of its digits is 720, while the sum is 22.

The square root of 2156431 is about 1468.4791452384. The cubic root of 2156431 is about 129.1948460660.

The spelling of 2156431 in words is "two million, one hundred fifty-six thousand, four hundred thirty-one".