21021213024 has 72 divisors (see below), whose sum is σ = 68318948880. Its totient is φ = 6006060288.

The previous prime is 21021213023. The next prime is 21021213029. The reversal of 21021213024 is 42031212012.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (72).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 21021212988 and 21021213006.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21021213023) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 5211579 + ... + 5215610.

It is an arithmetic number, because the mean of its divisors is an integer number (948874290).

Almost surely, 2^21021213024 is an apocalyptic number.

21021213024 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21021213024 is an abundant number, since it is smaller than the sum of its proper divisors (47297735856).

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

21021213024 is a wasteful number, since it uses less digits than its factorization.

21021213024 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10427212 (or 10427201 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

Adding to 21021213024 its reverse (42031212012), we get a palindrome (63052425036).

The spelling of 21021213024 in words is "twenty-one billion, twenty-one million, two hundred thirteen thousand, twenty-four".