21143657518 has 8 divisors (see below), whose sum is σ = 31726028520. Its totient is φ = 10568314680.

The previous prime is 21143657471. The next prime is 21143657569. The reversal of 21143657518 is 81575634112.

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

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, 1749513 + ... + 1761556.

It is an arithmetic number, because the mean of its divisors is an integer number (3965753565).

Almost surely, 2^21143657518 is an apocalyptic number.

21143657518 is a deficient number, since it is larger than the sum of its proper divisors (10582371002).

21143657518 is a wasteful number, since it uses less digits than its factorization.

21143657518 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3514082.

The product of its digits is 201600, while the sum is 43.

The spelling of 21143657518 in words is "twenty-one billion, one hundred forty-three million, six hundred fifty-seven thousand, five hundred eighteen".