133561440 has 192 divisors, whose sum is σ = 479001600. Its totient is φ = 34739712.

The previous prime is 133561411. The next prime is 133561447. The reversal of 133561440 is 44165331.

133561440 is a `hidden beast` number, since 1 + 3 + 3 + 5 + 614 + 40 = 666.

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 (133561447) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 185401 + ... + 186119.

It is an arithmetic number, because the mean of its divisors is an integer number (2494800).

Almost surely, 2^133561440 is an apocalyptic number.

133561440 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 133561440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (239500800).

133561440 is an abundant number, since it is smaller than the sum of its proper divisors (345440160).

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

133561440 is a wasteful number, since it uses less digits than its factorization.

133561440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 786 (or 772 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 27.

The square root of 133561440 is about 11556.8784712828. The cubic root of 133561440 is about 511.1641227659.

The spelling of 133561440 in words is "one hundred thirty-three million, five hundred sixty-one thousand, four hundred forty".