172820783520 has 576 divisors, whose sum is σ = 762519453696. Its totient is φ = 35910190080.

The previous prime is 172820783491. The next prime is 172820783521. The reversal of 172820783520 is 25387028271.

172820783520 is a `hidden beast` number, since 1 + 7 + 28 + 20 + 7 + 83 + 520 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is not an unprimeable number, because it can be changed into a prime (172820783521) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 2964897 + ... + 3022623.

It is an arithmetic number, because the mean of its divisors is an integer number (1323818496).

Almost surely, 2^172820783520 is an apocalyptic number.

172820783520 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 172820783520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (381259726848).

172820783520 is an abundant number, since it is smaller than the sum of its proper divisors (589698670176).

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

172820783520 is a wasteful number, since it uses less digits than its factorization.

172820783520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 57775 (or 57755 counting only the distinct ones).

The product of its (nonzero) digits is 376320, while the sum is 45.

The spelling of 172820783520 in words is "one hundred seventy-two billion, eight hundred twenty million, seven hundred eighty-three thousand, five hundred twenty".