81082477890 has 24 divisors (see below), whose sum is σ = 210814442748. Its totient is φ = 21621994080.

The previous prime is 81082477849. The next prime is 81082477943. The reversal of 81082477890 is 9877428018.

It is a happy number.

81082477890 is a `hidden beast` number, since 8 + 1 + 0 + 82 + 477 + 8 + 90 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 79407294849 + 1675183041 = 281793^2 + 40929^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 450458121 + ... + 450458300.

Almost surely, 2^81082477890 is an apocalyptic number.

81082477890 is an abundant number, since it is smaller than the sum of its proper divisors (129731964858).

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

81082477890 is a wasteful number, since it uses less digits than its factorization.

81082477890 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 900916434 (or 900916431 counting only the distinct ones).

The product of its (nonzero) digits is 1806336, while the sum is 54.

The spelling of 81082477890 in words is "eighty-one billion, eighty-two million, four hundred seventy-seven thousand, eight hundred ninety".