9913778388 has 18 divisors (see below), whose sum is σ = 25059828794. Its totient is φ = 3304592784.

The previous prime is 9913778387. The next prime is 9913778417. The reversal of 9913778388 is 8838773199.

It can be written as a sum of positive squares in only one way, i.e., 6734171844 + 3179606544 = 82062^2 + 56388^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9913778387) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 137691331 + ... + 137691402.

Almost surely, 2^9913778388 is an apocalyptic number.

It is an amenable number.

9913778388 is an abundant number, since it is smaller than the sum of its proper divisors (15146050406).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

9913778388 is a wasteful number, since it uses less digits than its factorization.

9913778388 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 275382743 (or 275382738 counting only the distinct ones).

The product of its digits is 18289152, while the sum is 63.

The square root of 9913778388 is about 99567.9586413220. The cubic root of 9913778388 is about 2148.2248472013.

The spelling of 9913778388 in words is "nine billion, nine hundred thirteen million, seven hundred seventy-eight thousand, three hundred eighty-eight".