2156197 has 4 divisors (see below), whose sum is σ = 2159136. Its totient is φ = 2153260.

The previous prime is 2156183. The next prime is 2156207. The reversal of 2156197 is 7916512.

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, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2156197 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 (2156117) 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, 672 + ... + 2182.

It is an arithmetic number, because the mean of its divisors is an integer number (539784).

2^2156197 is an apocalyptic number.

It is an amenable number.

2156197 is a deficient number, since it is larger than the sum of its proper divisors (2939).

2156197 is a wasteful number, since it uses less digits than its factorization.

2156197 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2938.

The product of its digits is 3780, while the sum is 31.

The square root of 2156197 is about 1468.3994688095. The cubic root of 2156197 is about 129.1901728061.

The spelling of 2156197 in words is "two million, one hundred fifty-six thousand, one hundred ninety-seven".