21133023444 has 180 divisors, whose sum is σ = 60398309664. Its totient is φ = 6439912128.

The previous prime is 21133023421. The next prime is 21133023449. The reversal of 21133023444 is 44432033112.

21133023444 is a `hidden beast` number, since 2 + 1 + 13 + 302 + 344 + 4 = 666.

It is a super-2 number, since 2×21133023444² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21133023449) by changing a digit.

It is a polite number, since it can be written in 59 ways as a sum of consecutive naturals, for example, 5857089 + ... + 5860695.

Almost surely, 2^21133023444 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21133023444, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30199154832).

21133023444 is an abundant number, since it is smaller than the sum of its proper divisors (39265286220).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21133023444 is a wasteful number, since it uses less digits than its factorization.

21133023444 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3756 (or 3732 counting only the distinct ones).

The product of its (nonzero) digits is 6912, while the sum is 27.

Adding to 21133023444 its reverse (44432033112), we get a palindrome (65565056556).

The spelling of 21133023444 in words is "twenty-one billion, one hundred thirty-three million, twenty-three thousand, four hundred forty-four".