21018075784 has 16 divisors (see below), whose sum is σ = 39411299520. Its totient is φ = 10508395920.

The previous prime is 21018075773. The next prime is 21018075791. The reversal of 21018075784 is 48757081012.

It is a self number, because there is not a number n which added to its sum of digits gives 21018075784.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 77029 + ... + 219019.

It is an arithmetic number, because the mean of its divisors is an integer number (2463206220).

Almost surely, 2^21018075784 is an apocalyptic number.

It is an amenable number.

21018075784 is a deficient number, since it is larger than the sum of its proper divisors (18393223736).

21018075784 is a wasteful number, since it uses less digits than its factorization.

21018075784 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 160500 (or 160496 counting only the distinct ones).

The product of its (nonzero) digits is 125440, while the sum is 43.

The spelling of 21018075784 in words is "twenty-one billion, eighteen million, seventy-five thousand, seven hundred eighty-four".