81894632 has 8 divisors (see below), whose sum is σ = 153552450. Its totient is φ = 40947312.

The previous prime is 81894611. The next prime is 81894641. The reversal of 81894632 is 23649818.

It can be written as a sum of positive squares in only one way, i.e., 81830116 + 64516 = 9046^2 + 254^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is a self number, because there is not a number n which added to its sum of digits gives 81894632.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5118407 + ... + 5118422.

Almost surely, 2^81894632 is an apocalyptic number.

It is an amenable number.

81894632 is a deficient number, since it is larger than the sum of its proper divisors (71657818).

81894632 is a wasteful number, since it uses less digits than its factorization.

81894632 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10236835 (or 10236831 counting only the distinct ones).

The product of its digits is 82944, while the sum is 41.

The square root of 81894632 is about 9049.5652934271. The cubic root of 81894632 is about 434.2619837234.

It can be divided in two parts, 8189 and 4632, that added together give a palindrome (12821).

The spelling of 81894632 in words is "eighty-one million, eight hundred ninety-four thousand, six hundred thirty-two".