101787920 has 80 divisors (see below), whose sum is σ = 257743920. Its totient is φ = 37158912.

The previous prime is 101787919. The next prime is 101787937. The reversal of 101787920 is 29787101.

101787920 = 976² + 977² + ... + 1072².

It is a Cunningham number, because it is equal to 10089²-1.

It can be written as a sum of positive squares in 8 ways, for example, as 14776336 + 87011584 = 3844^2 + 9328^2 .

It is a tau number, because it is divible by the number of its divisors (80).

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, 100376 + ... + 101384.

It is an arithmetic number, because the mean of its divisors is an integer number (3221799).

Almost surely, 2^101787920 is an apocalyptic number.

101787920 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 101787920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (128871960).

101787920 is an abundant number, since it is smaller than the sum of its proper divisors (155956000).

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

101787920 is a wasteful number, since it uses less digits than its factorization.

101787920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1132 (or 1126 counting only the distinct ones).

The product of its (nonzero) digits is 7056, while the sum is 35.

The square root of 101787920 is about 10088.9999504411. Note that the first 4 decimals coincide. The cubic root of 101787920 is about 466.9088221685.

The spelling of 101787920 in words is "one hundred one million, seven hundred eighty-seven thousand, nine hundred twenty".