21506260605054 has 8 divisors (see below), whose sum is σ = 43012521210120. Its totient is φ = 7168753535016.

The previous prime is 21506260605023. The next prime is 21506260605061. The reversal of 21506260605054 is 45050606260512.

It is a happy number.

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

21506260605054 is an admirable number.

It is a junction number, because it is equal to n+sod(n) for n = 21506260604997 and 21506260605015.

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, 1792188383749 + ... + 1792188383760.

It is an arithmetic number, because the mean of its divisors is an integer number (5376565151265).

Almost surely, 2^{21506260605054} is an apocalyptic number.

21506260605054 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

21506260605054 is a wasteful number, since it uses less digits than its factorization.

21506260605054 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3584376767514.

The product of its (nonzero) digits is 432000, while the sum is 42.

Adding to 21506260605054 its reverse (45050606260512), we get a palindrome (66556866865566).

The spelling of 21506260605054 in words is "twenty-one trillion, five hundred six billion, two hundred sixty million, six hundred five thousand, fifty-four".