74247821 has 6 divisors (see below), whose sum is σ = 76721166. Its totient is φ = 71851800.

The previous prime is 74247791. The next prime is 74247881. The reversal of 74247821 is 12874247.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 69538921 + 4708900 = 8339^2 + 2170^2 .

It is not a de Polignac number, because 74247821 - 2¹⁰ = 74246797 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (74247881) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 37670 + ... + 39591.

It is an arithmetic number, because the mean of its divisors is an integer number (12786861).

Almost surely, 2^74247821 is an apocalyptic number.

It is an amenable number.

74247821 is a deficient number, since it is larger than the sum of its proper divisors (2473345).

74247821 is an equidigital number, since it uses as much as digits as its factorization.

74247821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 77323 (or 77292 counting only the distinct ones).

The product of its digits is 25088, while the sum is 35.

The square root of 74247821 is about 8616.7175304753. The cubic root of 74247821 is about 420.3017880135.

The spelling of 74247821 in words is "seventy-four million, two hundred forty-seven thousand, eight hundred twenty-one".