21854899506 has 64 divisors (see below), whose sum is σ = 50457655296. Its totient is φ = 6245500800.

The previous prime is 21854899459. The next prime is 21854899513. The reversal of 21854899506 is 60599845812.

It is a happy number.

It is an unprimeable number.

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 31 ways as a sum of consecutive naturals, for example, 6390 + ... + 209166.

It is an arithmetic number, because the mean of its divisors is an integer number (788400864).

Almost surely, 2^21854899506 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21854899506, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25228827648).

21854899506 is an abundant number, since it is smaller than the sum of its proper divisors (28602755790).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21854899506 is a wasteful number, since it uses less digits than its factorization.

21854899506 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 202887.

The product of its (nonzero) digits is 6220800, while the sum is 57.

The spelling of 21854899506 in words is "twenty-one billion, eight hundred fifty-four million, eight hundred ninety-nine thousand, five hundred six".