74728221 has 4 divisors (see below), whose sum is σ = 99637632. Its totient is φ = 49818812.

The previous prime is 74728217. The next prime is 74728237. The reversal of 74728221 is 12282747.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 74728221 - 2² = 74728217 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (74728201) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 12454701 + ... + 12454706.

It is an arithmetic number, because the mean of its divisors is an integer number (24909408).

Almost surely, 2^74728221 is an apocalyptic number.

It is an amenable number.

74728221 is a deficient number, since it is larger than the sum of its proper divisors (24909411).

74728221 is a wasteful number, since it uses less digits than its factorization.

74728221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24909410.

The product of its digits is 12544, while the sum is 33.

The square root of 74728221 is about 8644.5486290494. The cubic root of 74728221 is about 421.2063221391.

The spelling of 74728221 in words is "seventy-four million, seven hundred twenty-eight thousand, two hundred twenty-one".