81222551668 has 24 divisors (see below), whose sum is σ = 142643743200. Its totient is φ = 40467422688.

The previous prime is 81222551653. The next prime is 81222551681. The reversal of 81222551668 is 86615522218.

It is a super-3 number, since 3×81222551668³ (a number of 34 digits) contains 333 as substring.

It is a congruent number.

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, 1442223 + ... + 1497481.

It is an arithmetic number, because the mean of its divisors is an integer number (5943489300).

Almost surely, 2^81222551668 is an apocalyptic number.

It is an amenable number.

81222551668 is a deficient number, since it is larger than the sum of its proper divisors (61421191532).

81222551668 is a wasteful number, since it uses less digits than its factorization.

81222551668 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 56559 (or 56557 counting only the distinct ones).

The product of its digits is 460800, while the sum is 46.

The spelling of 81222551668 in words is "eighty-one billion, two hundred twenty-two million, five hundred fifty-one thousand, six hundred sixty-eight".