2156551 has 4 divisors (see below), whose sum is σ = 2163672. Its totient is φ = 2149432.

The previous prime is 2156537. The next prime is 2156597. The reversal of 2156551 is 1556512.

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 2156551 - 2⁹ = 2156039 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2156521) 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, 3085 + ... + 3718.

It is an arithmetic number, because the mean of its divisors is an integer number (540918).

2^2156551 is an apocalyptic number.

2156551 is a deficient number, since it is larger than the sum of its proper divisors (7121).

2156551 is an equidigital number, since it uses as much as digits as its factorization.

2156551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7120.

The product of its digits is 1500, while the sum is 25.

The square root of 2156551 is about 1468.5200032686. The cubic root of 2156551 is about 129.1972424784.

The spelling of 2156551 in words is "two million, one hundred fifty-six thousand, five hundred fifty-one".