21155351050566 has 24 divisors (see below), whose sum is σ = 45846023590224. Its totient is φ = 7050332968560.

The previous prime is 21155351050553. The next prime is 21155351050633. The reversal of 21155351050566 is 66505015355112.

21155351050566 is a `hidden beast` number, since 2 + 1 + 1 + 5 + 5 + 35 + 1 + 0 + 50 + 566 = 666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 120802986 + ... + 120977981.

It is an arithmetic number, because the mean of its divisors is an integer number (1910250982926).

Almost surely, 2^{21155351050566} is an apocalyptic number.

21155351050566 is an abundant number, since it is smaller than the sum of its proper divisors (24690672539658).

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

21155351050566 is a wasteful number, since it uses less digits than its factorization.

21155351050566 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 241785836 (or 241785833 counting only the distinct ones).

The product of its (nonzero) digits is 675000, while the sum is 45.

The spelling of 21155351050566 in words is "twenty-one trillion, one hundred fifty-five billion, three hundred fifty-one million, fifty thousand, five hundred sixty-six".