74121721 has 2 divisors, whose sum is σ = 74121722. Its totient is φ = 74121720.

The previous prime is 74121703. The next prime is 74121731. The reversal of 74121721 is 12712147.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 44036496 + 30085225 = 6636^2 + 5485^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-74121721 is a prime.

It is not a weakly prime, because it can be changed into another prime (74121701) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 37060860 + 37060861.

It is an arithmetic number, because the mean of its divisors is an integer number (37060861).

Almost surely, 2^74121721 is an apocalyptic number.

It is an amenable number.

74121721 is a deficient number, since it is larger than the sum of its proper divisors (1).

74121721 is an equidigital number, since it uses as much as digits as its factorization.

74121721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 784, while the sum is 25.

The square root of 74121721 is about 8609.3972495175. The cubic root of 74121721 is about 420.0637110455.

Adding to 74121721 its reverse (12712147), we get a palindrome (86833868).

The spelling of 74121721 in words is "seventy-four million, one hundred twenty-one thousand, seven hundred twenty-one".