4156821 has 24 divisors (see below), whose sum is σ = 6349824. Its totient is φ = 2616480.

The previous prime is 4156819. The next prime is 4156829. The reversal of 4156821 is 1286514.

It is not a de Polignac number, because 4156821 - 2¹ = 4156819 is a prime.

It is an Ulam number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (4156829) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 12955 + ... + 13271.

It is an arithmetic number, because the mean of its divisors is an integer number (264576).

Almost surely, 2^4156821 is an apocalyptic number.

It is an amenable number.

4156821 is a deficient number, since it is larger than the sum of its proper divisors (2193003).

4156821 is a wasteful number, since it uses less digits than its factorization.

4156821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 401 (or 398 counting only the distinct ones).

The product of its digits is 1920, while the sum is 27.

The square root of 4156821 is about 2038.8283400031. The cubic root of 4156821 is about 160.7880523164.

The spelling of 4156821 in words is "four million, one hundred fifty-six thousand, eight hundred twenty-one".