6457081721 has 2 divisors, whose sum is σ = 6457081722. Its totient is φ = 6457081720.

The previous prime is 6457081693. The next prime is 6457081727. The reversal of 6457081721 is 1271807546.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 4024126096 + 2432955625 = 63436^2 + 49325^2 .

It is a cyclic number.

It is not a de Polignac number, because 6457081721 - 2¹⁴ = 6457065337 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (6457081727) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3228540860 + 3228540861.

It is an arithmetic number, because the mean of its divisors is an integer number (3228540861).

Almost surely, 2^6457081721 is an apocalyptic number.

It is an amenable number.

6457081721 is a deficient number, since it is larger than the sum of its proper divisors (1).

6457081721 is an equidigital number, since it uses as much as digits as its factorization.

6457081721 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 94080, while the sum is 41.

The square root of 6457081721 is about 80355.9687951057. The cubic root of 6457081721 is about 1862.1389930520.

The spelling of 6457081721 in words is "six billion, four hundred fifty-seven million, eighty-one thousand, seven hundred twenty-one".