21447203436 has 24 divisors (see below), whose sum is σ = 55603861040. Its totient is φ = 7149067776.

The previous prime is 21447203429. The next prime is 21447203447. The reversal of 21447203436 is 63430274412.

21447203436 is a `hidden beast` number, since 2 + 1 + 447 + 203 + 4 + 3 + 6 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 21447203436.

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, 99292501 + ... + 99292716.

Almost surely, 2^21447203436 is an apocalyptic number.

It is an amenable number.

21447203436 is an abundant number, since it is smaller than the sum of its proper divisors (34156657604).

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

21447203436 is a wasteful number, since it uses less digits than its factorization.

21447203436 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 198585230 (or 198585222 counting only the distinct ones).

The product of its (nonzero) digits is 96768, while the sum is 36.

Adding to 21447203436 its reverse (63430274412), we get a palindrome (84877477848).

The spelling of 21447203436 in words is "twenty-one billion, four hundred forty-seven million, two hundred three thousand, four hundred thirty-six".