991738100 has 18 divisors (see below), whose sum is σ = 2152071894. Its totient is φ = 396695200.

The previous prime is 991738093. The next prime is 991738103. The reversal of 991738100 is 1837199.

It can be written as a sum of positive squares in 3 ways, for example, as 1503076 + 990235024 = 1226^2 + 31468^2 .

It is a super-2 number, since 2×991738100² = 1967088917983220000, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (991738103) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 4958591 + ... + 4958790.

Almost surely, 2^991738100 is an apocalyptic number.

It is an amenable number.

991738100 is an abundant number, since it is smaller than the sum of its proper divisors (1160333794).

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

991738100 is a wasteful number, since it uses less digits than its factorization.

991738100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9917395 (or 9917388 counting only the distinct ones).

The product of its (nonzero) digits is 13608, while the sum is 38.

The square root of 991738100 is about 31491.8735549348. The cubic root of 991738100 is about 997.2384139964.

The spelling of 991738100 in words is "nine hundred ninety-one million, seven hundred thirty-eight thousand, one hundred".