21851348519 has 64 divisors (see below), whose sum is σ = 30221140992. Its totient is φ = 15247180800.

The previous prime is 21851348509. The next prime is 21851348527. The reversal of 21851348519 is 91584315812.

It is a happy number.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21851348519 is a prime.

It is a super-2 number, since 2×21851348519² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21851348509) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 16925264 + ... + 16926554.

It is an arithmetic number, because the mean of its divisors is an integer number (472205328).

Almost surely, 2^21851348519 is an apocalyptic number.

21851348519 is a deficient number, since it is larger than the sum of its proper divisors (8369792473).

21851348519 is a wasteful number, since it uses less digits than its factorization.

21851348519 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1816.

The product of its digits is 345600, while the sum is 47.

The spelling of 21851348519 in words is "twenty-one billion, eight hundred fifty-one million, three hundred forty-eight thousand, five hundred nineteen".