21139996816 has 45 divisors (see below), whose sum is σ = 41397200019. Its totient is φ = 10458043488.

The previous prime is 21139996793. The next prime is 21139996841. The reversal of 21139996816 is 61869993112.

The square root of 21139996816 is 145396.

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

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 94798081 + ... + 94798303.

Almost surely, 2^21139996816 is an apocalyptic number.

21139996816 is the 145396-th square number.

It is an amenable number.

21139996816 is a deficient number, since it is larger than the sum of its proper divisors (20257203203).

21139996816 is an frugal number, since it uses more digits than its factorization.

21139996816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 780 (or 388 counting only the distinct ones).

The product of its digits is 1259712, while the sum is 55.

The spelling of 21139996816 in words is "twenty-one billion, one hundred thirty-nine million, nine hundred ninety-six thousand, eight hundred sixteen".