81218081020 has 12 divisors (see below), whose sum is σ = 170557970184. Its totient is φ = 32487232400.

The previous prime is 81218080969. The next prime is 81218081059. The reversal of 81218081020 is 2018081218.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2030452006 + ... + 2030452045.

It is an arithmetic number, because the mean of its divisors is an integer number (14213164182).

Almost surely, 2^81218081020 is an apocalyptic number.

It is an amenable number.

81218081020 is an abundant number, since it is smaller than the sum of its proper divisors (89339889164).

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

81218081020 is a wasteful number, since it uses less digits than its factorization.

81218081020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4060904060 (or 4060904058 counting only the distinct ones).

The product of its (nonzero) digits is 2048, while the sum is 31.

The spelling of 81218081020 in words is "eighty-one billion, two hundred eighteen million, eighty-one thousand, twenty".