81445732 has 12 divisors (see below), whose sum is σ = 146382460. Its totient is φ = 39622176.

The previous prime is 81445729. The next prime is 81445747. The reversal of 81445732 is 23754418.

It can be written as a sum of positive squares in 2 ways, for example, as 36072036 + 45373696 = 6006^2 + 6736^2 .

It is a super-2 number, since 2×81445732² = 13266814522031648, which contains 22 as substring.

It is a hoax number, since the sum of its digits (34) coincides with the sum of the digits of its distinct prime factors.

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 in 3 ways as a sum of consecutive naturals, for example, 275007 + ... + 275302.

Almost surely, 2^81445732 is an apocalyptic number.

It is an amenable number.

81445732 is a deficient number, since it is larger than the sum of its proper divisors (64936728).

81445732 is a wasteful number, since it uses less digits than its factorization.

81445732 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 550350 (or 550348 counting only the distinct ones).

The product of its digits is 26880, while the sum is 34.

The square root of 81445732 is about 9024.7289155963. The cubic root of 81445732 is about 433.4670700956.

It can be divided in two parts, 81445 and 732, that multiplied together give a triangular number (59617740 = T₁₀₉₁₉).

The spelling of 81445732 in words is "eighty-one million, four hundred forty-five thousand, seven hundred thirty-two".