101999980 has 48 divisors (see below), whose sum is σ = 228624480. Its totient is φ = 38112768.

The previous prime is 101999969. The next prime is 102000023. The reversal of 101999980 is 89999101.

It is a self number, because there is not a number n which added to its sum of digits gives 101999980.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 25902 + ... + 29578.

It is an arithmetic number, because the mean of its divisors is an integer number (4763010).

Almost surely, 2^101999980 is an apocalyptic number.

101999980 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 101999980, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (114312240).

101999980 is an abundant number, since it is smaller than the sum of its proper divisors (126624500).

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

101999980 is a wasteful number, since it uses less digits than its factorization.

101999980 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3778 (or 3776 counting only the distinct ones).

The product of its (nonzero) digits is 52488, while the sum is 46.

The square root of 101999980 is about 10099.5039482145. The cubic root of 101999980 is about 467.2328422974.

The spelling of 101999980 in words is "one hundred one million, nine hundred ninety-nine thousand, nine hundred eighty".