74815721 has 2 divisors, whose sum is σ = 74815722. Its totient is φ = 74815720.

The previous prime is 74815703. The next prime is 74815771. The reversal of 74815721 is 12751847.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 74580496 + 235225 = 8636^2 + 485^2 .

It is a cyclic number.

It is not a de Polignac number, because 74815721 - 2²⁶ = 7706857 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (74815771) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 37407860 + 37407861.

It is an arithmetic number, because the mean of its divisors is an integer number (37407861).

Almost surely, 2^74815721 is an apocalyptic number.

It is an amenable number.

74815721 is a deficient number, since it is larger than the sum of its proper divisors (1).

74815721 is an equidigital number, since it uses as much as digits as its factorization.

74815721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 15680, while the sum is 35.

The square root of 74815721 is about 8649.6081414131. The cubic root of 74815721 is about 421.3706562073.

The spelling of 74815721 in words is "seventy-four million, eight hundred fifteen thousand, seven hundred twenty-one".