7664632781 has 8 divisors (see below), whose sum is σ = 8304861600. Its totient is φ = 7031638512.

The previous prime is 7664632763. The next prime is 7664632793. The reversal of 7664632781 is 1872364667.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-7664632781 is a prime.

It is a super-2 number, since 2×7664632781² (a number of 21 digits) 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 (7664632081) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1806431 + ... + 1810668.

It is an arithmetic number, because the mean of its divisors is an integer number (1038107700).

Almost surely, 2^7664632781 is an apocalyptic number.

It is an amenable number.

7664632781 is a deficient number, since it is larger than the sum of its proper divisors (640228819).

7664632781 is a wasteful number, since it uses less digits than its factorization.

7664632781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3617275.

The product of its digits is 2032128, while the sum is 50.

The square root of 7664632781 is about 87547.8885010941. Note that the first 3 decimals coincide. The cubic root of 7664632781 is about 1971.6528495012.

The spelling of 7664632781 in words is "seven billion, six hundred sixty-four million, six hundred thirty-two thousand, seven hundred eighty-one".