79921835668 has 6 divisors (see below), whose sum is σ = 139863212426. Its totient is φ = 39960917832.

The previous prime is 79921835659. The next prime is 79921835677. The reversal of 79921835668 is 86653812997.

It is an interprime number because it is at equal distance from previous prime (79921835659) and next prime (79921835677).

It can be written as a sum of positive squares in only one way, i.e., 72458949124 + 7462886544 = 269182^2 + 86388^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9990229455 + ... + 9990229462.

Almost surely, 2^79921835668 is an apocalyptic number.

It is an amenable number.

79921835668 is a deficient number, since it is larger than the sum of its proper divisors (59941376758).

79921835668 is a wasteful number, since it uses less digits than its factorization.

79921835668 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19980458921 (or 19980458919 counting only the distinct ones).

The product of its digits is 39191040, while the sum is 64.

The spelling of 79921835668 in words is "seventy-nine billion, nine hundred twenty-one million, eight hundred thirty-five thousand, six hundred sixty-eight".