81054909 has 48 divisors (see below), whose sum is σ = 131751984. Its totient is φ = 47692800.

The previous prime is 81054899. The next prime is 81054937. The reversal of 81054909 is 90945018.

It can be written as a sum of positive squares in 8 ways, for example, as 54243225 + 26811684 = 7365^2 + 5178^2 .

It is not a de Polignac number, because 81054909 - 2⁷ = 81054781 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81054989) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 292479 + ... + 292755.

It is an arithmetic number, because the mean of its divisors is an integer number (2744833).

Almost surely, 2^81054909 is an apocalyptic number.

It is an amenable number.

81054909 is a deficient number, since it is larger than the sum of its proper divisors (50697075).

81054909 is a wasteful number, since it uses less digits than its factorization.

81054909 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 398 (or 395 counting only the distinct ones).

The product of its (nonzero) digits is 12960, while the sum is 36.

The square root of 81054909 is about 9003.0499832001. The cubic root of 81054909 is about 432.7726175044.

The spelling of 81054909 in words is "eighty-one million, fifty-four thousand, nine hundred nine".