21003424040 has 32 divisors (see below), whose sum is σ = 47270121480. Its totient is φ = 8399162112.

The previous prime is 21003424037. The next prime is 21003424051. The reversal of 21003424040 is 4042430012.

It can be written as a sum of positive squares in 4 ways, for example, as 16091937316 + 4911486724 = 126854^2 + 70082^2 .

It is a super-2 number, since 2×21003424040² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 89654 + ... + 223706.

Almost surely, 2^21003424040 is an apocalyptic number.

21003424040 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21003424040 is an abundant number, since it is smaller than the sum of its proper divisors (26266697440).

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

21003424040 is a wasteful number, since it uses less digits than its factorization.

21003424040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 137981 (or 137977 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 20.

Adding to 21003424040 its reverse (4042430012), we get a palindrome (25045854052).

The spelling of 21003424040 in words is "twenty-one billion, three million, four hundred twenty-four thousand, forty".