21210133331 has 4 divisors (see below), whose sum is σ = 21214259352. Its totient is φ = 21206007312.

The previous prime is 21210133291. The next prime is 21210133369. The reversal of 21210133331 is 13333101212.

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 21210133331 - 2³⁰ = 20136391507 is a prime.

It is a super-2 number, since 2×21210133331² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21210133831) 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, 2055290 + ... + 2065583.

It is an arithmetic number, because the mean of its divisors is an integer number (5303564838).

Almost surely, 2^21210133331 is an apocalyptic number.

21210133331 is a deficient number, since it is larger than the sum of its proper divisors (4126021).

21210133331 is an equidigital number, since it uses as much as digits as its factorization.

21210133331 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4126020.

The product of its (nonzero) digits is 324, while the sum is 20.

Adding to 21210133331 its reverse (13333101212), we get a palindrome (34543234543).

The spelling of 21210133331 in words is "twenty-one billion, two hundred ten million, one hundred thirty-three thousand, three hundred thirty-one".