667776731 has 2 divisors, whose sum is σ = 667776732. Its totient is φ = 667776730.

The previous prime is 667776671. The next prime is 667776743. The reversal of 667776731 is 137677766.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-667776731 is a prime.

It is a super-3 number, since 3×667776731³ (a number of 27 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a self number, because there is not a number n which added to its sum of digits gives 667776731.

It is not a weakly prime, because it can be changed into another prime (667776761) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 333888365 + 333888366.

It is an arithmetic number, because the mean of its divisors is an integer number (333888366).

Almost surely, 2^667776731 is an apocalyptic number.

667776731 is a deficient number, since it is larger than the sum of its proper divisors (1).

667776731 is an equidigital number, since it uses as much as digits as its factorization.

667776731 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1555848, while the sum is 50.

The square root of 667776731 is about 25841.3763371845. The cubic root of 667776731 is about 874.0650611273.

The spelling of 667776731 in words is "six hundred sixty-seven million, seven hundred seventy-six thousand, seven hundred thirty-one".