991439910 has 48 divisors (see below), whose sum is σ = 2604341376. Its totient is φ = 261656064.

The previous prime is 991439899. The next prime is 991439921. The reversal of 991439910 is 19934199.

It is an interprime number because it is at equal distance from previous prime (991439899) and next prime (991439921).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 48054 + ... + 65513.

It is an arithmetic number, because the mean of its divisors is an integer number (54257112).

Almost surely, 2^991439910 is an apocalyptic number.

991439910 is a gapful number since it is divisible by the number (90) formed by its first and last digit.

991439910 is an abundant number, since it is smaller than the sum of its proper divisors (1612901466).

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

991439910 is a wasteful number, since it uses less digits than its factorization.

991439910 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 113677 (or 113674 counting only the distinct ones).

The product of its (nonzero) digits is 78732, while the sum is 45.

The square root of 991439910 is about 31487.1388030097. The cubic root of 991439910 is about 997.1384560434.

The spelling of 991439910 in words is "nine hundred ninety-one million, four hundred thirty-nine thousand, nine hundred ten".