133231621 has 2 divisors, whose sum is σ = 133231622. Its totient is φ = 133231620.

The previous prime is 133231619. The next prime is 133231649. The reversal of 133231621 is 126132331.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 94965025 + 38266596 = 9745^2 + 6186^2 .

It is a cyclic number.

It is not a de Polignac number, because 133231621 - 2¹ = 133231619 is a prime.

Together with 133231619, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 133231592 and 133231601.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (133231121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 66615810 + 66615811.

It is an arithmetic number, because the mean of its divisors is an integer number (66615811).

Almost surely, 2^133231621 is an apocalyptic number.

It is an amenable number.

133231621 is a deficient number, since it is larger than the sum of its proper divisors (1).

133231621 is an equidigital number, since it uses as much as digits as its factorization.

133231621 is an evil number, because the sum of its binary digits is even.

The product of its digits is 648, while the sum is 22.

The square root of 133231621 is about 11542.6002703030. The cubic root of 133231621 is about 510.7430166819.

Adding to 133231621 its reverse (126132331), we get a palindrome (259363952).

The spelling of 133231621 in words is "one hundred thirty-three million, two hundred thirty-one thousand, six hundred twenty-one".