81640462352 has 10 divisors (see below), whose sum is σ = 158178395838. Its totient is φ = 40820231168.

The previous prime is 81640462327. The next prime is 81640462381. The reversal of 81640462352 is 25326404618.

It can be written as a sum of positive squares in only one way, i.e., 61585370896 + 20055091456 = 248164^2 + 141616^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2551264433 + ... + 2551264464.

Almost surely, 2^81640462352 is an apocalyptic number.

It is an amenable number.

81640462352 is a deficient number, since it is larger than the sum of its proper divisors (76537933486).

81640462352 is a wasteful number, since it uses less digits than its factorization.

81640462352 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5102528905 (or 5102528899 counting only the distinct ones).

The product of its (nonzero) digits is 276480, while the sum is 41.

The spelling of 81640462352 in words is "eighty-one billion, six hundred forty million, four hundred sixty-two thousand, three hundred fifty-two".