74021821 has 2 divisors, whose sum is σ = 74021822. Its totient is φ = 74021820.

The previous prime is 74021747. The next prime is 74021873. The reversal of 74021821 is 12812047.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 73359225 + 662596 = 8565^2 + 814^2 .

It is a cyclic number.

It is not a de Polignac number, because 74021821 - 2¹⁵ = 73989053 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (74021881) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 37010910 + 37010911.

It is an arithmetic number, because the mean of its divisors is an integer number (37010911).

Almost surely, 2^74021821 is an apocalyptic number.

It is an amenable number.

74021821 is a deficient number, since it is larger than the sum of its proper divisors (1).

74021821 is an equidigital number, since it uses as much as digits as its factorization.

74021821 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 896, while the sum is 25.

The square root of 74021821 is about 8603.5934934189. The cubic root of 74021821 is about 419.8749079468.

Adding to 74021821 its reverse (12812047), we get a palindrome (86833868).

The spelling of 74021821 in words is "seventy-four million, twenty-one thousand, eight hundred twenty-one".