81490942820 has 24 divisors (see below), whose sum is σ = 195578263104. Its totient is φ = 27939751776.

The previous prime is 81490942751. The next prime is 81490942837. The reversal of 81490942820 is 2824909418.

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 291038942 + ... + 291039221.

It is an arithmetic number, because the mean of its divisors is an integer number (8149094296).

Almost surely, 2^81490942820 is an apocalyptic number.

It is an amenable number.

81490942820 is an abundant number, since it is smaller than the sum of its proper divisors (114087320284).

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

81490942820 is a wasteful number, since it uses less digits than its factorization.

81490942820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 582078179 (or 582078177 counting only the distinct ones).

The product of its (nonzero) digits is 331776, while the sum is 47.

The spelling of 81490942820 in words is "eighty-one billion, four hundred ninety million, nine hundred forty-two thousand, eight hundred twenty".