21211331424 has 24 divisors (see below), whose sum is σ = 55679745240. Its totient is φ = 7070443776.

The previous prime is 21211331419. The next prime is 21211331431. The reversal of 21211331424 is 42413311212.

It is a tau number, because it is divible by the number of its divisors (24).

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a nude number because it is divisible by every one of its digits.

It is a junction number, because it is equal to n+sod(n) for n = 21211331394 and 21211331403.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 110475589 + ... + 110475780.

It is an arithmetic number, because the mean of its divisors is an integer number (2319989385).

Almost surely, 2^21211331424 is an apocalyptic number.

21211331424 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21211331424 is an abundant number, since it is smaller than the sum of its proper divisors (34468413816).

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

21211331424 is a wasteful number, since it uses less digits than its factorization.

21211331424 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 220951382 (or 220951374 counting only the distinct ones).

The product of its digits is 1152, while the sum is 24.

Adding to 21211331424 its reverse (42413311212), we get a palindrome (63624642636).

The spelling of 21211331424 in words is "twenty-one billion, two hundred eleven million, three hundred thirty-one thousand, four hundred twenty-four".