77993578651 has 4 divisors (see below), whose sum is σ = 79061983912. Its totient is φ = 76925173392.

The previous prime is 77993578643. The next prime is 77993578679. The reversal of 77993578651 is 15687539977.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 15687539977 = 30029 ⋅522413.

It is a cyclic number.

It is not a de Polignac number, because 77993578651 - 2³ = 77993578643 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (77993578601) 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, 534202521 + ... + 534202666.

It is an arithmetic number, because the mean of its divisors is an integer number (19765495978).

Almost surely, 2^77993578651 is an apocalyptic number.

77993578651 is a deficient number, since it is larger than the sum of its proper divisors (1068405261).

77993578651 is a wasteful number, since it uses less digits than its factorization.

77993578651 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1068405260.

The product of its digits is 100018800, while the sum is 67.

The spelling of 77993578651 in words is "seventy-seven billion, nine hundred ninety-three million, five hundred seventy-eight thousand, six hundred fifty-one".