21431606436 has 36 divisors (see below), whose sum is σ = 55434210832. Its totient is φ = 6977731824.

The previous prime is 21431606431. The next prime is 21431606467. The reversal of 21431606436 is 63460613412.

21431606436 is a `hidden beast` number, since 2 + 1 + 4 + 3 + 1 + 6 + 0 + 643 + 6 = 666.

It is a tau number, because it is divible by the number of its divisors (36).

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 21431606436.

It is not an unprimeable number, because it can be changed into a prime (21431606431) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 6920806 + ... + 6923901.

Almost surely, 2^21431606436 is an apocalyptic number.

It is an amenable number.

21431606436 is an abundant number, since it is smaller than the sum of its proper divisors (34002604396).

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

21431606436 is a wasteful number, since it uses less digits than its factorization.

21431606436 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13844760 (or 13844755 counting only the distinct ones).

The product of its (nonzero) digits is 62208, while the sum is 36.

The spelling of 21431606436 in words is "twenty-one billion, four hundred thirty-one million, six hundred six thousand, four hundred thirty-six".