2156405 has 8 divisors (see below), whose sum is σ = 2724000. Its totient is φ = 1634256.

The previous prime is 2156393. The next prime is 2156417. The reversal of 2156405 is 5046512.

It is an interprime number because it is at equal distance from previous prime (2156393) and next prime (2156417).

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 2156405 - 2¹⁰ = 2155381 is a prime.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11255 + ... + 11444.

It is an arithmetic number, because the mean of its divisors is an integer number (340500).

2^2156405 is an apocalyptic number.

It is an amenable number.

2156405 is a deficient number, since it is larger than the sum of its proper divisors (567595).

2156405 is a wasteful number, since it uses less digits than its factorization.

2156405 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22723.

The product of its (nonzero) digits is 1200, while the sum is 23.

The square root of 2156405 is about 1468.4702925153. The cubic root of 2156405 is about 129.1943268316.

The spelling of 2156405 in words is "two million, one hundred fifty-six thousand, four hundred five".