117821520 has 80 divisors (see below), whose sum is σ = 405837120. Its totient is φ = 31418496.

The previous prime is 117821513. The next prime is 117821521. The reversal of 117821520 is 25128711.

117821520 is a `hidden beast` number, since 117 + 8 + 21 + 520 = 666.

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

It is a super-2 number, since 2×117821520² = 27763821150220800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (117821521) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 25114 + ... + 29433.

It is an arithmetic number, because the mean of its divisors is an integer number (5072964).

Almost surely, 2^117821520 is an apocalyptic number.

117821520 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

117821520 is an abundant number, since it is smaller than the sum of its proper divisors (288015600).

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

117821520 is a wasteful number, since it uses less digits than its factorization.

117821520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 54569 (or 54557 counting only the distinct ones).

The product of its (nonzero) digits is 1120, while the sum is 27.

The square root of 117821520 is about 10854.5621744960. The cubic root of 117821520 is about 490.2393943372.

It can be divided in two parts, 117821 and 520, that added together give a triangular number (118341 = T₄₈₆).

The spelling of 117821520 in words is "one hundred seventeen million, eight hundred twenty-one thousand, five hundred twenty".