133171220 has 72 divisors (see below), whose sum is σ = 350376264. Its totient is φ = 42142464.

The previous prime is 133171193. The next prime is 133171223. The reversal of 133171220 is 22171331.

It can be written as a sum of positive squares in 4 ways, for example, as 25260676 + 107910544 = 5026^2 + 10388^2 .

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a junction number, because it is equal to n+sod(n) for n = 133171192 and 133171201.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (133171223) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 7514 + ... + 17966.

It is an arithmetic number, because the mean of its divisors is an integer number (4866337).

Almost surely, 2^133171220 is an apocalyptic number.

133171220 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 133171220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (175188132).

133171220 is an abundant number, since it is smaller than the sum of its proper divisors (217205044).

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

133171220 is a wasteful number, since it uses less digits than its factorization.

133171220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10489 (or 10480 counting only the distinct ones).

The product of its (nonzero) digits is 252, while the sum is 20.

The square root of 133171220 is about 11539.9835355169. The cubic root of 133171220 is about 510.6658226650.

The spelling of 133171220 in words is "one hundred thirty-three million, one hundred seventy-one thousand, two hundred twenty".