21043542436 has 48 divisors (see below), whose sum is σ = 42278544000. Its totient is φ = 8977736448.

The previous prime is 21043542427. The next prime is 21043542437. The reversal of 21043542436 is 63424534012.

It is not an unprimeable number, because it can be changed into a prime (21043542437) 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, 6377115 + ... + 6380413.

It is an arithmetic number, because the mean of its divisors is an integer number (880803000).

Almost surely, 2^21043542436 is an apocalyptic number.

It is an amenable number.

21043542436 is an abundant number, since it is smaller than the sum of its proper divisors (21235001564).

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

21043542436 is a wasteful number, since it uses less digits than its factorization.

21043542436 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4276 (or 4274 counting only the distinct ones).

The product of its (nonzero) digits is 69120, while the sum is 34.

The spelling of 21043542436 in words is "twenty-one billion, forty-three million, five hundred forty-two thousand, four hundred thirty-six".