21516783745 has 8 divisors (see below), whose sum is σ = 25822257984. Its totient is φ = 17212015344.

The previous prime is 21516783733. The next prime is 21516783787. The reversal of 21516783745 is 54738761512.

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

It is a cyclic number.

It is not a de Polignac number, because 21516783745 - 2¹⁷ = 21516652673 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 106899 + ... + 233368.

It is an arithmetic number, because the mean of its divisors is an integer number (3227782248).

Almost surely, 2^21516783745 is an apocalyptic number.

It is an amenable number.

21516783745 is a deficient number, since it is larger than the sum of its proper divisors (4305474239).

21516783745 is a wasteful number, since it uses less digits than its factorization.

21516783745 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 352919.

The product of its digits is 1411200, while the sum is 49.

The spelling of 21516783745 in words is "twenty-one billion, five hundred sixteen million, seven hundred eighty-three thousand, seven hundred forty-five".