21002434040 has 64 divisors (see below), whose sum is σ = 54034214400. Its totient is φ = 7197107328.

The previous prime is 21002434039. The next prime is 21002434043. The reversal of 21002434040 is 4043420012.

It is a super-2 number, since 2×21002434040² (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 a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21002434043) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 552527 + ... + 589313.

It is an arithmetic number, because the mean of its divisors is an integer number (844284600).

Almost surely, 2^21002434040 is an apocalyptic number.

21002434040 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21002434040 is an abundant number, since it is smaller than the sum of its proper divisors (33031780360).

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

21002434040 is a wasteful number, since it uses less digits than its factorization.

21002434040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38844 (or 38840 counting only the distinct ones).

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

Adding to 21002434040 its reverse (4043420012), we get a palindrome (25045854052).

The spelling of 21002434040 in words is "twenty-one billion, two million, four hundred thirty-four thousand, forty".