98991990 has 64 divisors (see below), whose sum is σ = 272517120. Its totient is φ = 25544160.

The previous prime is 98991973. The next prime is 98992001. The reversal of 98991990 is 9919989.

98991990 = T₂₂₆ + T₂₂₇ + ... + T₈₄₅.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2457 + ... + 14283.

It is an arithmetic number, because the mean of its divisors is an integer number (4258080).

Almost surely, 2^98991990 is an apocalyptic number.

98991990 is a gapful number since it is divisible by the number (90) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 98991990, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (136258560).

98991990 is an abundant number, since it is smaller than the sum of its proper divisors (173525130).

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

98991990 is a wasteful number, since it uses less digits than its factorization.

98991990 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11874 (or 11868 counting only the distinct ones).

The product of its (nonzero) digits is 472392, while the sum is 54.

The square root of 98991990 is about 9949.4718452790. The cubic root of 98991990 is about 462.5940242246.

The spelling of 98991990 in words is "ninety-eight million, nine hundred ninety-one thousand, nine hundred ninety".