78899371909 has 4 divisors (see below), whose sum is σ = 81031787404. Its totient is φ = 76766956416.

The previous prime is 78899371841. The next prime is 78899371949. The reversal of 78899371909 is 90917399887.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 76016004100 + 2883367809 = 275710^2 + 53697^2 .

It is a cyclic number.

It is not a de Polignac number, because 78899371909 - 2⁷ = 78899371781 is a prime.

It is a super-2 number, since 2×78899371909² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78899371949) 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, 1066207692 + ... + 1066207765.

It is an arithmetic number, because the mean of its divisors is an integer number (20257946851).

Almost surely, 2^78899371909 is an apocalyptic number.

It is an amenable number.

78899371909 is a deficient number, since it is larger than the sum of its proper divisors (2132415495).

78899371909 is a wasteful number, since it uses less digits than its factorization.

78899371909 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2132415494.

The product of its (nonzero) digits is 61725888, while the sum is 70.

The spelling of 78899371909 in words is "seventy-eight billion, eight hundred ninety-nine million, three hundred seventy-one thousand, nine hundred nine".