133531663 has 4 divisors (see below), whose sum is σ = 137839168. Its totient is φ = 129224160.

The previous prime is 133531661. The next prime is 133531667. The reversal of 133531663 is 366135331.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 133531663 - 2¹ = 133531661 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (31), and also a Moran number because the ratio is a prime number: 4307473 = 133531663 / (1 + 3 + 3 + 5 + 3 + 1 + 6 + 6 + 3).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (133531661) 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, 2153706 + ... + 2153767.

It is an arithmetic number, because the mean of its divisors is an integer number (34459792).

Almost surely, 2^133531663 is an apocalyptic number.

133531663 is a deficient number, since it is larger than the sum of its proper divisors (4307505).

133531663 is an equidigital number, since it uses as much as digits as its factorization.

133531663 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4307504.

The product of its digits is 14580, while the sum is 31.

The square root of 133531663 is about 11555.5901190722. The cubic root of 133531663 is about 511.1261325960.

Adding to 133531663 its reverse (366135331), we get a palindrome (499666994).

The spelling of 133531663 in words is "one hundred thirty-three million, five hundred thirty-one thousand, six hundred sixty-three".