74217821 has 4 divisors (see below), whose sum is σ = 74266752. Its totient is φ = 74168892.

The previous prime is 74217809. The next prime is 74217823. The reversal of 74217821 is 12871247.

It is a happy number.

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 74217821 - 2²² = 70023517 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 (74217823) 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, 22115 + ... + 25248.

It is an arithmetic number, because the mean of its divisors is an integer number (18566688).

Almost surely, 2^74217821 is an apocalyptic number.

It is an amenable number.

74217821 is a deficient number, since it is larger than the sum of its proper divisors (48931).

74217821 is a wasteful number, since it uses less digits than its factorization.

74217821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 48930.

The product of its digits is 6272, while the sum is 32.

The square root of 74217821 is about 8614.9765524928. The cubic root of 74217821 is about 420.2451724249.

The spelling of 74217821 in words is "seventy-four million, two hundred seventeen thousand, eight hundred twenty-one".