21041516566 has 16 divisors (see below), whose sum is σ = 36682548480. Its totient is φ = 8864948520.

The previous prime is 21041516537. The next prime is 21041516593. The reversal of 21041516566 is 66561514012.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12736170 + ... + 12737821.

It is an arithmetic number, because the mean of its divisors is an integer number (2292659280).

Almost surely, 2^21041516566 is an apocalyptic number.

21041516566 is a deficient number, since it is larger than the sum of its proper divisors (15641031914).

21041516566 is a wasteful number, since it uses less digits than its factorization.

21041516566 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25474059.

The product of its (nonzero) digits is 43200, while the sum is 37.

It can be divided in two parts, 210415 and 16566, that added together give a cube (226981 = 61³).

The spelling of 21041516566 in words is "twenty-one billion, forty-one million, five hundred sixteen thousand, five hundred sixty-six".