133531021 has 4 divisors (see below), whose sum is σ = 143802652. Its totient is φ = 123259392.

The previous prime is 133531019. The next prime is 133531033. The reversal of 133531021 is 120135331.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 120135331 = 109 ⋅1102159.

It can be written as a sum of positive squares in 2 ways, for example, as 18826921 + 114704100 = 4339^2 + 10710^2 .

It is a cyclic number.

It is not a de Polignac number, because 133531021 - 2¹ = 133531019 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 133531021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (133531001) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5135796 + ... + 5135821.

It is an arithmetic number, because the mean of its divisors is an integer number (35950663).

Almost surely, 2^133531021 is an apocalyptic number.

It is an amenable number.

133531021 is a deficient number, since it is larger than the sum of its proper divisors (10271631).

133531021 is a wasteful number, since it uses less digits than its factorization.

133531021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10271630.

The product of its (nonzero) digits is 270, while the sum is 19.

The square root of 133531021 is about 11555.5623402758. The cubic root of 133531021 is about 511.1253134557.

Adding to 133531021 its reverse (120135331), we get a palindrome (253666352).

It can be divided in two parts, 1335310 and 21, that added together give a palindrome (1335331).

The spelling of 133531021 in words is "one hundred thirty-three million, five hundred thirty-one thousand, twenty-one".