1078747721 has 2 divisors, whose sum is σ = 1078747722. Its totient is φ = 1078747720.

The previous prime is 1078747697. The next prime is 1078747739. The reversal of 1078747721 is 1277478701.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 820020496 + 258727225 = 28636^2 + 16085^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1078747721 is a prime.

It is not a weakly prime, because it can be changed into another prime (1078747921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 539373860 + 539373861.

It is an arithmetic number, because the mean of its divisors is an integer number (539373861).

Almost surely, 2^1078747721 is an apocalyptic number.

It is an amenable number.

1078747721 is a deficient number, since it is larger than the sum of its proper divisors (1).

1078747721 is an equidigital number, since it uses as much as digits as its factorization.

1078747721 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 153664, while the sum is 44.

The square root of 1078747721 is about 32844.2951058475. The cubic root of 1078747721 is about 1025.5888651999.

The spelling of 1078747721 in words is "one billion, seventy-eight million, seven hundred forty-seven thousand, seven hundred twenty-one".