78643650021 has 8 divisors (see below), whose sum is σ = 104865132960. Its totient is φ = 52425633552.

The previous prime is 78643650011. The next prime is 78643650023. The reversal of 78643650021 is 12005634687.

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

It is not a de Polignac number, because 78643650021 - 2⁵ = 78643649989 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78643650023) 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, 813210 + ... + 904763.

It is an arithmetic number, because the mean of its divisors is an integer number (13108141620).

Almost surely, 2^78643650021 is an apocalyptic number.

It is an amenable number.

78643650021 is a deficient number, since it is larger than the sum of its proper divisors (26221482939).

78643650021 is a wasteful number, since it uses less digits than its factorization.

78643650021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1733235.

The product of its (nonzero) digits is 241920, while the sum is 42.

The spelling of 78643650021 in words is "seventy-eight billion, six hundred forty-three million, six hundred fifty thousand, twenty-one".