21252551620066 has 48 divisors (see below), whose sum is σ = 36905104065024. Its totient is φ = 9142247492352.

The previous prime is 21252551620051. The next prime is 21252551620067. The reversal of 21252551620066 is 66002615525212.

It is a super-2 number, since 2×21252551620066² (a number of 27 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21252551620067) by changing a digit.

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 23 ways as a sum of consecutive naturals, for example, 17362866 + ... + 18546541.

It is an arithmetic number, because the mean of its divisors is an integer number (768856334688).

Almost surely, 2^{21252551620066} is an apocalyptic number.

21252551620066 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

21252551620066 is a deficient number, since it is larger than the sum of its proper divisors (15652552444958).

21252551620066 is a wasteful number, since it uses less digits than its factorization.

21252551620066 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35909555 (or 35909542 counting only the distinct ones).

The product of its (nonzero) digits is 432000, while the sum is 43.

The spelling of 21252551620066 in words is "twenty-one trillion, two hundred fifty-two billion, five hundred fifty-one million, six hundred twenty thousand, sixty-six".