78505791649 has 16 divisors (see below), whose sum is σ = 82847232000. Its totient is φ = 74185569360.

The previous prime is 78505791643. The next prime is 78505791653. The reversal of 78505791649 is 94619750587.

It is a cyclic number.

It is not a de Polignac number, because 78505791649 - 2³³ = 69915857057 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78505791643) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 14191014 + ... + 14196544.

It is an arithmetic number, because the mean of its divisors is an integer number (5177952000).

Almost surely, 2^78505791649 is an apocalyptic number.

It is an amenable number.

78505791649 is a deficient number, since it is larger than the sum of its proper divisors (4341440351).

78505791649 is a wasteful number, since it uses less digits than its factorization.

78505791649 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7308.

The product of its (nonzero) digits is 19051200, while the sum is 61.

The spelling of 78505791649 in words is "seventy-eight billion, five hundred five million, seven hundred ninety-one thousand, six hundred forty-nine".