766465991 has 4 divisors (see below), whose sum is σ = 779457000. Its totient is φ = 753474984.

The previous prime is 766465981. The next prime is 766466009. The reversal of 766465991 is 199564667.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-766465991 is a prime.

It is a super-2 number, since 2×766465991² = 1174940230719224162, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (766465901) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6495416 + ... + 6495533.

It is an arithmetic number, because the mean of its divisors is an integer number (194864250).

Almost surely, 2^766465991 is an apocalyptic number.

766465991 is a deficient number, since it is larger than the sum of its proper divisors (12991009).

766465991 is a wasteful number, since it uses less digits than its factorization.

766465991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12991008.

The product of its digits is 2449440, while the sum is 53.

The square root of 766465991 is about 27685.1221958654. The cubic root of 766465991 is about 915.1612647371.

The spelling of 766465991 in words is "seven hundred sixty-six million, four hundred sixty-five thousand, nine hundred ninety-one".