21504610206066 has 64 divisors (see below), whose sum is σ = 46403629848576. Its totient is φ = 6604518772800.

The previous prime is 21504610206049. The next prime is 21504610206071. The reversal of 21504610206066 is 66060201640512.

It is a super-2 number, since 2×21504610206066² (a number of 27 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 561649575 + ... + 561687861.

It is an arithmetic number, because the mean of its divisors is an integer number (725056716384).

Almost surely, 2^{21504610206066} is an apocalyptic number.

21504610206066 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

21504610206066 is an abundant number, since it is smaller than the sum of its proper divisors (24899019642510).

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

21504610206066 is a wasteful number, since it uses less digits than its factorization.

21504610206066 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 51487.

The product of its (nonzero) digits is 103680, while the sum is 39.

Adding to 21504610206066 its reverse (66060201640512), we get a palindrome (87564811846578).

The spelling of 21504610206066 in words is "twenty-one trillion, five hundred four billion, six hundred ten million, two hundred six thousand, sixty-six".