133320021 has 4 divisors (see below), whose sum is σ = 177760032. Its totient is φ = 88880012.

The previous prime is 133319993. The next prime is 133320049. The reversal of 133320021 is 120023331.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is an interprime number because it is at equal distance from previous prime (133319993) and next prime (133320049).

It is a cyclic number.

It is not a de Polignac number, because 133320021 - 2¹⁸ = 133057877 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (133320071) 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, 22220001 + ... + 22220006.

It is an arithmetic number, because the mean of its divisors is an integer number (44440008).

Almost surely, 2^133320021 is an apocalyptic number.

It is an amenable number.

133320021 is a deficient number, since it is larger than the sum of its proper divisors (44440011).

133320021 is an equidigital number, since it uses as much as digits as its factorization.

133320021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44440010.

The product of its (nonzero) digits is 108, while the sum is 15.

The square root of 133320021 is about 11546.4289284610. The cubic root of 133320021 is about 510.8559520855.

Adding to 133320021 its reverse (120023331), we get a palindrome (253343352).

The spelling of 133320021 in words is "one hundred thirty-three million, three hundred twenty thousand, twenty-one".