21258202066 has 16 divisors (see below), whose sum is σ = 32649656544. Its totient is φ = 10377791424.

The previous prime is 21258202051. The next prime is 21258202073. The reversal of 21258202066 is 66020285212.

It is a super-2 number, since 2×21258202066² (a number of 21 digits) contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 686820 + ... + 717103.

It is an arithmetic number, because the mean of its divisors is an integer number (2040603534).

Almost surely, 2^21258202066 is an apocalyptic number.

21258202066 is a deficient number, since it is larger than the sum of its proper divisors (11391454478).

21258202066 is a wasteful number, since it uses less digits than its factorization.

21258202066 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1404105.

The product of its (nonzero) digits is 23040, while the sum is 34.

Adding to 21258202066 its reverse (66020285212), we get a palindrome (87278487278).

The spelling of 21258202066 in words is "twenty-one billion, two hundred fifty-eight million, two hundred two thousand, sixty-six".