7149721 has 4 divisors (see below), whose sum is σ = 7186212. Its totient is φ = 7113232.

The previous prime is 7149713. The next prime is 7149731. The reversal of 7149721 is 1279417.

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 3463321 + 3686400 = 1861^2 + 1920^2 .

It is a cyclic number.

It is not a de Polignac number, because 7149721 - 2³ = 7149713 is a prime.

It is a super-2 number, since 2×7149721² = 102237020755682, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (7149731) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 17950 + ... + 18343.

It is an arithmetic number, because the mean of its divisors is an integer number (1796553).

Almost surely, 2^7149721 is an apocalyptic number.

It is an amenable number.

7149721 is a deficient number, since it is larger than the sum of its proper divisors (36491).

7149721 is a wasteful number, since it uses less digits than its factorization.

7149721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36490.

The product of its digits is 3528, while the sum is 31.

The square root of 7149721 is about 2673.8962208732. The cubic root of 7149721 is about 192.6473465672.

The spelling of 7149721 in words is "seven million, one hundred forty-nine thousand, seven hundred twenty-one".