21012231424 has 36 divisors (see below), whose sum is σ = 42248603124. Its totient is φ = 10429411328.

The previous prime is 21012231397. The next prime is 21012231479. The reversal of 21012231424 is 42413221012.

It can be written as a sum of positive squares in 2 ways, for example, as 8100000000 + 12912231424 = 90000^2 + 113632^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21012231395 and 21012231404.

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, 264487 + ... + 334630.

It is an arithmetic number, because the mean of its divisors is an integer number (1173572309).

Almost surely, 2^21012231424 is an apocalyptic number.

It is an amenable number.

21012231424 is an abundant number, since it is smaller than the sum of its proper divisors (21236371700).

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

21012231424 is an equidigital number, since it uses as much as digits as its factorization.

21012231424 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 599270 (or 599256 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 22.

Adding to 21012231424 its reverse (42413221012), we get a palindrome (63425452436).

The spelling of 21012231424 in words is "twenty-one billion, twelve million, two hundred thirty-one thousand, four hundred twenty-four".