81354221608 has 32 divisors (see below), whose sum is σ = 169226820000. Its totient is φ = 36352423360.

The previous prime is 81354221593. The next prime is 81354221609. The reversal of 81354221608 is 80612245318.

It is not an unprimeable number, because it can be changed into a prime (81354221609) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7829383 + ... + 7839766.

It is an arithmetic number, because the mean of its divisors is an integer number (5288338125).

Almost surely, 2^81354221608 is an apocalyptic number.

81354221608 is a gapful number since it is divisible by the number (88) formed by its first and last digit.

It is an amenable number.

81354221608 is an abundant number, since it is smaller than the sum of its proper divisors (87872598392).

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

81354221608 is a wasteful number, since it uses less digits than its factorization.

81354221608 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15669225 (or 15669221 counting only the distinct ones).

The product of its (nonzero) digits is 92160, while the sum is 40.

The spelling of 81354221608 in words is "eighty-one billion, three hundred fifty-four million, two hundred twenty-one thousand, six hundred eight".