21851348518 has 4 divisors (see below), whose sum is σ = 32777022780. Its totient is φ = 10925674258.

The previous prime is 21851348509. The next prime is 21851348527. The reversal of 21851348518 is 81584315812.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (21851348509) and next prime (21851348527).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5462837128 + ... + 5462837131.

It is an arithmetic number, because the mean of its divisors is an integer number (8194255695).

Almost surely, 2^21851348518 is an apocalyptic number.

21851348518 is a deficient number, since it is larger than the sum of its proper divisors (10925674262).

21851348518 is a wasteful number, since it uses less digits than its factorization.

21851348518 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10925674261.

The product of its digits is 307200, while the sum is 46.

The spelling of 21851348518 in words is "twenty-one billion, eight hundred fifty-one million, three hundred forty-eight thousand, five hundred eighteen".