815482721 has 2 divisors, whose sum is σ = 815482722. Its totient is φ = 815482720.

The previous prime is 815482711. The next prime is 815482757. The reversal of 815482721 is 127284518.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 803155600 + 12327121 = 28340^2 + 3511^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-815482721 is a prime.

It is not a weakly prime, because it can be changed into another prime (815482711) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 407741360 + 407741361.

It is an arithmetic number, because the mean of its divisors is an integer number (407741361).

Almost surely, 2^815482721 is an apocalyptic number.

It is an amenable number.

815482721 is a deficient number, since it is larger than the sum of its proper divisors (1).

815482721 is an equidigital number, since it uses as much as digits as its factorization.

815482721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 35840, while the sum is 38.

The square root of 815482721 is about 28556.6580852872. The cubic root of 815482721 is about 934.2682449832.

The spelling of 815482721 in words is "eight hundred fifteen million, four hundred eighty-two thousand, seven hundred twenty-one".