21728748742 has 16 divisors (see below), whose sum is σ = 33725185200. Its totient is φ = 10487201760.

The previous prime is 21728748739. The next prime is 21728748763. The reversal of 21728748742 is 24784782712.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 21728748742.

It is a congruent number.

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, 208492 + ... + 294832.

It is an arithmetic number, because the mean of its divisors is an integer number (2107824075).

Almost surely, 2^21728748742 is an apocalyptic number.

21728748742 is a deficient number, since it is larger than the sum of its proper divisors (11996436458).

21728748742 is a wasteful number, since it uses less digits than its factorization.

21728748742 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 90711.

The product of its digits is 2809856, while the sum is 52.

The spelling of 21728748742 in words is "twenty-one billion, seven hundred twenty-eight million, seven hundred forty-eight thousand, seven hundred forty-two".