81801044 has 24 divisors (see below), whose sum is σ = 154788648. Its totient is φ = 37601280.

The previous prime is 81801029. The next prime is 81801047. The reversal of 81801044 is 44010818.

It can be written as a sum of positive squares in 4 ways, for example, as 7496644 + 74304400 = 2738^2 + 8620^2 .

It is a Harshad number since it is a multiple of its sum of digits (26).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81801047) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10304 + ... + 16424.

It is an arithmetic number, because the mean of its divisors is an integer number (6449527).

Almost surely, 2^81801044 is an apocalyptic number.

It is an amenable number.

81801044 is a deficient number, since it is larger than the sum of its proper divisors (72987604).

81801044 is a wasteful number, since it uses less digits than its factorization.

81801044 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6395 (or 6393 counting only the distinct ones).

The product of its (nonzero) digits is 1024, while the sum is 26.

The square root of 81801044 is about 9044.3929591764. The cubic root of 81801044 is about 434.0964978995.

The spelling of 81801044 in words is "eighty-one million, eight hundred one thousand, forty-four".