81500444 has 12 divisors (see below), whose sum is σ = 145660704. Its totient is φ = 39883104.

The previous prime is 81500407. The next prime is 81500449. The reversal of 81500444 is 44400518.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81500449) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 216569 + ... + 216944.

It is an arithmetic number, because the mean of its divisors is an integer number (12138392).

Almost surely, 2^81500444 is an apocalyptic number.

It is an amenable number.

81500444 is a deficient number, since it is larger than the sum of its proper divisors (64160260).

81500444 is a wasteful number, since it uses less digits than its factorization.

81500444 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 433564 (or 433562 counting only the distinct ones).

The product of its (nonzero) digits is 2560, while the sum is 26.

The square root of 81500444 is about 9027.7596334860. The cubic root of 81500444 is about 433.5641103426.

The spelling of 81500444 in words is "eighty-one million, five hundred thousand, four hundred forty-four".