7447221 has 24 divisors (see below), whose sum is σ = 11749920. Its totient is φ = 4700592.

The previous prime is 7447217. The next prime is 7447243. The reversal of 7447221 is 1227447.

It is a happy number.

It is not a de Polignac number, because 7447221 - 2² = 7447217 is a prime.

It is a super-2 number, since 2×7447221² = 110922201245682, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Curzon number.

7447221 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7447201) 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, 3811 + ... + 5423.

It is an arithmetic number, because the mean of its divisors is an integer number (489580).

Almost surely, 2^7447221 is an apocalyptic number.

It is an amenable number.

7447221 is a deficient number, since it is larger than the sum of its proper divisors (4302699).

7447221 is a wasteful number, since it uses less digits than its factorization.

7447221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1647 (or 1635 counting only the distinct ones).

The product of its digits is 3136, while the sum is 27.

The square root of 7447221 is about 2728.9596918973. The cubic root of 7447221 is about 195.2831389806.

The spelling of 7447221 in words is "seven million, four hundred forty-seven thousand, two hundred twenty-one".