9978938655 has 16 divisors (see below), whose sum is σ = 18247202304. Its totient is φ = 4561800480.

The previous prime is 9978938653. The next prime is 9978938687. The reversal of 9978938655 is 5568398799.

It is not a de Polignac number, because 9978938655 - 2¹ = 9978938653 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 9978938655.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9978938653) 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, 47518651 + ... + 47518860.

It is an arithmetic number, because the mean of its divisors is an integer number (1140450144).

Almost surely, 2^9978938655 is an apocalyptic number.

9978938655 is a deficient number, since it is larger than the sum of its proper divisors (8268263649).

9978938655 is a wasteful number, since it uses less digits than its factorization.

9978938655 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 95037526.

The product of its digits is 146966400, while the sum is 69.

The square root of 9978938655 is about 99894.6377690014. The cubic root of 9978938655 is about 2152.9211171952.

The spelling of 9978938655 in words is "nine billion, nine hundred seventy-eight million, nine hundred thirty-eight thousand, six hundred fifty-five".