4156921 has 2 divisors, whose sum is σ = 4156922. Its totient is φ = 4156920.

The previous prime is 4156909. The next prime is 4156937. The reversal of 4156921 is 1296514.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 3534400 + 622521 = 1880^2 + 789^2 .

It is a cyclic number.

It is not a de Polignac number, because 4156921 - 2⁷ = 4156793 is a prime.

It is an Ulam number.

It is equal to p₂₉₃₄₇₃ and since 4156921 and 293473 have the same sum of digits, it is a Honaker prime.

It is a self number, because there is not a number n which added to its sum of digits gives 4156921.

It is not a weakly prime, because it can be changed into another prime (4156981) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2078460 + 2078461.

It is an arithmetic number, because the mean of its divisors is an integer number (2078461).

Almost surely, 2^4156921 is an apocalyptic number.

It is an amenable number.

4156921 is a deficient number, since it is larger than the sum of its proper divisors (1).

4156921 is an equidigital number, since it uses as much as digits as its factorization.

4156921 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2160, while the sum is 28.

The square root of 4156921 is about 2038.8528637447. The cubic root of 4156921 is about 160.7893416572.

The spelling of 4156921 in words is "four million, one hundred fifty-six thousand, nine hundred twenty-one".