133121540 has 12 divisors (see below), whose sum is σ = 279555276. Its totient is φ = 53248608.

The previous prime is 133121537. The next prime is 133121561. The reversal of 133121540 is 45121331.

It can be written as a sum of positive squares in 2 ways, for example, as 29855296 + 103266244 = 5464^2 + 10162^2 .

It is a Harshad number since it is a multiple of its sum of digits (20), and also a Moran number because the ratio is a prime number: 6656077 = 133121540 / (1 + 3 + 3 + 1 + 2 + 1 + 5 + 4 + 0).

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3328019 + ... + 3328058.

It is an arithmetic number, because the mean of its divisors is an integer number (23296273).

Almost surely, 2^133121540 is an apocalyptic number.

133121540 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

133121540 is an abundant number, since it is smaller than the sum of its proper divisors (146433736).

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

133121540 is a wasteful number, since it uses less digits than its factorization.

133121540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6656086 (or 6656084 counting only the distinct ones).

The product of its (nonzero) digits is 360, while the sum is 20.

The square root of 133121540 is about 11537.8308186591. The cubic root of 133121540 is about 510.6023128629.

Adding to 133121540 its reverse (45121331), we get a palindrome (178242871).

The spelling of 133121540 in words is "one hundred thirty-three million, one hundred twenty-one thousand, five hundred forty".