764657749561 has 2 divisors, whose sum is σ = 764657749562. Its totient is φ = 764657749560.

The previous prime is 764657749517. The next prime is 764657749567. The reversal of 764657749561 is 165947756467.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 454916525625 + 309741223936 = 674475^2 + 556544^2 .

It is an emirp because it is prime and its reverse (165947756467) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 764657749561 - 2⁹ = 764657749049 is a prime.

It is not a weakly prime, because it can be changed into another prime (764657749567) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 382328874780 + 382328874781.

It is an arithmetic number, because the mean of its divisors is an integer number (382328874781).

Almost surely, 2^764657749561 is an apocalyptic number.

It is an amenable number.

764657749561 is a deficient number, since it is larger than the sum of its proper divisors (1).

764657749561 is an equidigital number, since it uses as much as digits as its factorization.

764657749561 is an evil number, because the sum of its binary digits is even.

The product of its digits is 266716800, while the sum is 67.

The spelling of 764657749561 in words is "seven hundred sixty-four billion, six hundred fifty-seven million, seven hundred forty-nine thousand, five hundred sixty-one".