9990561838 has 16 divisors (see below), whose sum is σ = 15143203296. Its totient is φ = 4942903680.

The previous prime is 9990561829. The next prime is 9990561839. The reversal of 9990561838 is 8381650999.

It is a super-2 number, since 2×9990561838² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9990561839) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 253770 + ... + 290482.

It is an arithmetic number, because the mean of its divisors is an integer number (946450206).

Almost surely, 2^9990561838 is an apocalyptic number.

9990561838 is a deficient number, since it is larger than the sum of its proper divisors (5152641458).

9990561838 is a wasteful number, since it uses less digits than its factorization.

9990561838 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38139.

The product of its (nonzero) digits is 4199040, while the sum is 58.

The square root of 9990561838 is about 99952.7980498795. The cubic root of 9990561838 is about 2153.7566798940.

The spelling of 9990561838 in words is "nine billion, nine hundred ninety million, five hundred sixty-one thousand, eight hundred thirty-eight".