21678439696 has 15 divisors (see below), whose sum is σ = 42003118021. Its totient is φ = 10838925376.

The previous prime is 21678439609. The next prime is 21678439829. The reversal of 21678439696 is 69693487612.

The square root of 21678439696 is 147236.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 7998798096 + 13679641600 = 89436^2 + 116960^2 .

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 570540 + ... + 607348.

Almost surely, 2^21678439696 is an apocalyptic number.

21678439696 is the 147236-th square number.

It is an amenable number.

21678439696 is a deficient number, since it is larger than the sum of its proper divisors (20324678325).

21678439696 is an frugal number, since it uses more digits than its factorization.

21678439696 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 73626 (or 36811 counting only the distinct ones).

The product of its digits is 23514624, while the sum is 61.

The spelling of 21678439696 in words is "twenty-one billion, six hundred seventy-eight million, four hundred thirty-nine thousand, six hundred ninety-six".