7156721 has 8 divisors (see below), whose sum is σ = 8408064. Its totient is φ = 6005520.

The previous prime is 7156717. The next prime is 7156727. The reversal of 7156721 is 1276517.

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 7156721 - 2² = 7156717 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (7156727) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 24881 + ... + 25166.

It is an arithmetic number, because the mean of its divisors is an integer number (1051008).

Almost surely, 2^7156721 is an apocalyptic number.

It is an amenable number.

7156721 is a deficient number, since it is larger than the sum of its proper divisors (1251343).

7156721 is a wasteful number, since it uses less digits than its factorization.

7156721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 50071.

The product of its digits is 2940, while the sum is 29.

The square root of 7156721 is about 2675.2048519693. The cubic root of 7156721 is about 192.7101971114.

The spelling of 7156721 in words is "seven million, one hundred fifty-six thousand, seven hundred twenty-one".