81044989 has 4 divisors (see below), whose sum is σ = 81344320. Its totient is φ = 80745660.

The previous prime is 81044983. The next prime is 81044993. The reversal of 81044989 is 98944018.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 81044989 - 2¹⁵ = 81012221 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81044983) 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, 149259 + ... + 149800.

It is an arithmetic number, because the mean of its divisors is an integer number (20336080).

Almost surely, 2^81044989 is an apocalyptic number.

It is an amenable number.

81044989 is a deficient number, since it is larger than the sum of its proper divisors (299331).

81044989 is a wasteful number, since it uses less digits than its factorization.

81044989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 299330.

The product of its (nonzero) digits is 82944, while the sum is 43.

The square root of 81044989 is about 9002.4990419327. The cubic root of 81044989 is about 432.7549616561.

The spelling of 81044989 in words is "eighty-one million, forty-four thousand, nine hundred eighty-nine".