21031220133 has 96 divisors (see below), whose sum is σ = 39389156352. Its totient is φ = 10894176000.

The previous prime is 21031220129. The next prime is 21031220173. The reversal of 21031220133 is 33102213012.

It is not a de Polignac number, because 21031220133 - 2² = 21031220129 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21031220173) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 7501710 + ... + 7504512.

It is an arithmetic number, because the mean of its divisors is an integer number (410303712).

Almost surely, 2^21031220133 is an apocalyptic number.

It is an amenable number.

21031220133 is a deficient number, since it is larger than the sum of its proper divisors (18357936219).

21031220133 is a wasteful number, since it uses less digits than its factorization.

21031220133 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3237 (or 3225 counting only the distinct ones).

The product of its (nonzero) digits is 216, while the sum is 18.

Adding to 21031220133 its reverse (33102213012), we get a palindrome (54133433145).

The spelling of 21031220133 in words is "twenty-one billion, thirty-one million, two hundred twenty thousand, one hundred thirty-three".