81649031884 has 36 divisors (see below), whose sum is σ = 170706702544. Its totient is φ = 33471025632.

The previous prime is 81649031869. The next prime is 81649031921. The reversal of 81649031884 is 48813094618.

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, 2741367 + ... + 2770990.

Almost surely, 2^81649031884 is an apocalyptic number.

It is an amenable number.

81649031884 is an abundant number, since it is smaller than the sum of its proper divisors (89057670660).

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

81649031884 is a wasteful number, since it uses less digits than its factorization.

81649031884 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5512414 (or 5512389 counting only the distinct ones).

The product of its (nonzero) digits is 1327104, while the sum is 52.

The spelling of 81649031884 in words is "eighty-one billion, six hundred forty-nine million, thirty-one thousand, eight hundred eighty-four".