81144999 has 36 divisors (see below), whose sum is σ = 130186056. Its totient is φ = 48390048.

The previous prime is 81144997. The next prime is 81145039. The reversal of 81144999 is 99944118.

It is not a de Polignac number, because 81144999 - 2¹ = 81144997 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81144997) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 638874 + ... + 639000.

Almost surely, 2^81144999 is an apocalyptic number.

81144999 is a deficient number, since it is larger than the sum of its proper divisors (49041057).

81144999 is a wasteful number, since it uses less digits than its factorization.

81144999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 316 (or 186 counting only the distinct ones).

The product of its digits is 93312, while the sum is 45.

The square root of 81144999 is about 9008.0518981631. The cubic root of 81144999 is about 432.9328958871.

The spelling of 81144999 in words is "eighty-one million, one hundred forty-four thousand, nine hundred ninety-nine".