21043413540 has 72 divisors (see below), whose sum is σ = 64165989888. Its totient is φ = 5582187840.

The previous prime is 21043413527. The next prime is 21043413557. The reversal of 21043413540 is 4531434012.

It is a happy number.

21043413540 is a `hidden beast` number, since 2 + 104 + 3 + 4 + 13 + 540 = 666.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 271662 + ... + 340421.

It is an arithmetic number, because the mean of its divisors is an integer number (891194304).

Almost surely, 2^21043413540 is an apocalyptic number.

21043413540 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21043413540 is an abundant number, since it is smaller than the sum of its proper divisors (43122576348).

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

21043413540 is a wasteful number, since it uses less digits than its factorization.

21043413540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 612289 (or 612284 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 27.

Adding to 21043413540 its reverse (4531434012), we get a palindrome (25574847552).

The spelling of 21043413540 in words is "twenty-one billion, forty-three million, four hundred thirteen thousand, five hundred forty".