21133213444 has 24 divisors (see below), whose sum is σ = 42640472448. Its totient is φ = 8976938880.

The previous prime is 21133213357. The next prime is 21133213457. The reversal of 21133213444 is 44431233112.

It is a happy number.

It is a super-2 number, since 2×21133213444² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (28).

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3336472 + ... + 3342799.

It is an arithmetic number, because the mean of its divisors is an integer number (1776686352).

Almost surely, 2^21133213444 is an apocalyptic number.

It is an amenable number.

21133213444 is an abundant number, since it is smaller than the sum of its proper divisors (21507259004).

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

21133213444 is a wasteful number, since it uses less digits than its factorization.

21133213444 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6679395 (or 6679393 counting only the distinct ones).

The product of its digits is 6912, while the sum is 28.

Adding to 21133213444 its reverse (44431233112), we get a palindrome (65564446556).

The spelling of 21133213444 in words is "twenty-one billion, one hundred thirty-three million, two hundred thirteen thousand, four hundred forty-four".