21043421144540 has 24 divisors (see below), whose sum is σ = 46790665839792. Its totient is φ = 7922229136640.

The previous prime is 21043421144539. The next prime is 21043421144561. The reversal of 21043421144540 is 4544112434012.

It is a self number, because there is not a number n which added to its sum of digits gives 21043421144540.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 30946207226 + ... + 30946207905.

It is an arithmetic number, because the mean of its divisors is an integer number (1949611076658).

Almost surely, 2^{21043421144540} is an apocalyptic number.

21043421144540 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21043421144540 is an abundant number, since it is smaller than the sum of its proper divisors (25747244695252).

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

21043421144540 is a wasteful number, since it uses less digits than its factorization.

21043421144540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 61892415157 (or 61892415155 counting only the distinct ones).

The product of its (nonzero) digits is 61440, while the sum is 35.

Adding to 21043421144540 its reverse (4544112434012), we get a palindrome (25587533578552).

The spelling of 21043421144540 in words is "twenty-one trillion, forty-three billion, four hundred twenty-one million, one hundred forty-four thousand, five hundred forty".