21056437742 has 8 divisors (see below), whose sum is σ = 31664216136. Its totient is φ = 10501699032.

The previous prime is 21056437729. The next prime is 21056437771. The reversal of 21056437742 is 24773465012.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a self number, because there is not a number n which added to its sum of digits gives 21056437742.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13258928 + ... + 13260515.

It is an arithmetic number, because the mean of its divisors is an integer number (3958027017).

Almost surely, 2^21056437742 is an apocalyptic number.

21056437742 is a deficient number, since it is larger than the sum of its proper divisors (10607778394).

21056437742 is a wasteful number, since it uses less digits than its factorization.

21056437742 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26519842.

The product of its (nonzero) digits is 282240, while the sum is 41.

The spelling of 21056437742 in words is "twenty-one billion, fifty-six million, four hundred thirty-seven thousand, seven hundred forty-two".