7156921 has 4 divisors (see below), whose sum is σ = 7196644. Its totient is φ = 7117200.

The previous prime is 7156913. The next prime is 7156927. The reversal of 7156921 is 1296517.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 60025 + 7096896 = 245^2 + 2664^2 .

It is a cyclic number.

It is not a de Polignac number, because 7156921 - 2³ = 7156913 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (7156927) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 19590 + ... + 19951.

It is an arithmetic number, because the mean of its divisors is an integer number (1799161).

Almost surely, 2^7156921 is an apocalyptic number.

It is an amenable number.

7156921 is a deficient number, since it is larger than the sum of its proper divisors (39723).

7156921 is a wasteful number, since it uses less digits than its factorization.

7156921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39722.

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

The square root of 7156921 is about 2675.2422320231. The cubic root of 7156921 is about 192.7119922389.

The spelling of 7156921 in words is "seven million, one hundred fifty-six thousand, nine hundred twenty-one".