7981764857 has 4 divisors (see below), whose sum is σ = 8707379856. Its totient is φ = 7256149860.

The previous prime is 7981764823. The next prime is 7981764871. The reversal of 7981764857 is 7584671897.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 7981764857 - 2¹⁰ = 7981763833 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 7981764857.

It is not an unprimeable number, because it can be changed into a prime (7981764887) 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, 362807483 + ... + 362807504.

It is an arithmetic number, because the mean of its divisors is an integer number (2176844964).

Almost surely, 2^7981764857 is an apocalyptic number.

It is an amenable number.

7981764857 is a deficient number, since it is larger than the sum of its proper divisors (725614999).

7981764857 is a wasteful number, since it uses less digits than its factorization.

7981764857 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 725614998.

The product of its digits is 23708160, while the sum is 62.

The square root of 7981764857 is about 89340.7233964445. The cubic root of 7981764857 is about 1998.4792487008.

The spelling of 7981764857 in words is "seven billion, nine hundred eighty-one million, seven hundred sixty-four thousand, eight hundred fifty-seven".