21365506566054 has 192 divisors, whose sum is σ = 57143931840000. Its totient is φ = 5893018028352.

The previous prime is 21365506566029. The next prime is 21365506566067. The reversal of 21365506566054 is 45066560556312.

21365506566054 is a `hidden beast` number, since 2 + 1 + 36 + 5 + 506 + 56 + 6 + 0 + 54 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 604569517 + ... + 604604855.

It is an arithmetic number, because the mean of its divisors is an integer number (297624645000).

Almost surely, 2^{21365506566054} is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21365506566054, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28571965920000).

21365506566054 is an abundant number, since it is smaller than the sum of its proper divisors (35778425273946).

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

21365506566054 is a wasteful number, since it uses less digits than its factorization.

21365506566054 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43272 (or 43259 counting only the distinct ones).

The product of its (nonzero) digits is 19440000, while the sum is 54.

The spelling of 21365506566054 in words is "twenty-one trillion, three hundred sixty-five billion, five hundred six million, five hundred sixty-six thousand, fifty-four".