9978261826 has 96 divisors (see below), whose sum is σ = 18028830960. Its totient is φ = 4097974272.

The previous prime is 9978261791. The next prime is 9978261841. The reversal of 9978261826 is 6281628799.

It can be written as a sum of positive squares in 8 ways, for example, as 1687977225 + 8290284601 = 41085^2 + 91051^2 .

It is a Harshad number since it is a multiple of its sum of digits (58).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 88303146 + ... + 88303258.

Almost surely, 2^9978261826 is an apocalyptic number.

9978261826 is the 49946-th decagonal number.

9978261826 is a deficient number, since it is larger than the sum of its proper divisors (8050569134).

9978261826 is a wasteful number, since it uses less digits than its factorization.

9978261826 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 340 (or 257 counting only the distinct ones).

The product of its digits is 5225472, while the sum is 58.

The square root of 9978261826 is about 99891.2499971844. The cubic root of 9978261826 is about 2152.8724415981.

The spelling of 9978261826 in words is "nine billion, nine hundred seventy-eight million, two hundred sixty-one thousand, eight hundred twenty-six".