21003505718 has 8 divisors (see below), whose sum is σ = 33928740048. Its totient is φ = 9693925704.

The previous prime is 21003505709. The next prime is 21003505727. The reversal of 21003505718 is 81750530012.

It is an interprime number because it is at equal distance from previous prime (21003505709) and next prime (21003505727).

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

It is a super-2 number, since 2×21003505718² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

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, 403913546 + ... + 403913597.

It is an arithmetic number, because the mean of its divisors is an integer number (4241092506).

Almost surely, 2^21003505718 is an apocalyptic number.

21003505718 is a deficient number, since it is larger than the sum of its proper divisors (12925234330).

21003505718 is a wasteful number, since it uses less digits than its factorization.

21003505718 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 807827158.

The product of its (nonzero) digits is 8400, while the sum is 32.

The spelling of 21003505718 in words is "twenty-one billion, three million, five hundred five thousand, seven hundred eighteen".