105661920 has 384 divisors, whose sum is σ = 426746880. Its totient is φ = 21381120.

The previous prime is 105661909. The next prime is 105661921. The reversal of 105661920 is 29166501.

105661920 = 98² + 99² + ... + 682².

It is a super-2 number, since 2×105661920² = 22328882676172800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (105661921) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 1790851 + ... + 1790909.

It is an arithmetic number, because the mean of its divisors is an integer number (1111320).

Almost surely, 2^105661920 is an apocalyptic number.

105661920 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 105661920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (213373440).

105661920 is an abundant number, since it is smaller than the sum of its proper divisors (321084960).

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

105661920 is a wasteful number, since it uses less digits than its factorization.

105661920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 138 (or 130 counting only the distinct ones).

The product of its (nonzero) digits is 3240, while the sum is 30.

The square root of 105661920 is about 10279.1984123277. The cubic root of 105661920 is about 472.7586669127.

The spelling of 105661920 in words is "one hundred five million, six hundred sixty-one thousand, nine hundred twenty".