81498910909 has 8 divisors (see below), whose sum is σ = 87914103032. Its totient is φ = 75104582400.

The previous prime is 81498910903. The next prime is 81498910931. The reversal of 81498910909 is 90901989418.

It can be written as a sum of positive squares in 4 ways, for example, as 16295288409 + 65203622500 = 127653^2 + 255350^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 81498910909 - 2¹⁹ = 81498386621 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 (81498910903) 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, 5207784 + ... + 5223409.

It is an arithmetic number, because the mean of its divisors is an integer number (10989262879).

Almost surely, 2^81498910909 is an apocalyptic number.

It is an amenable number.

81498910909 is a deficient number, since it is larger than the sum of its proper divisors (6415192123).

81498910909 is a wasteful number, since it uses less digits than its factorization.

81498910909 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10431807.

The product of its (nonzero) digits is 1679616, while the sum is 58.

The spelling of 81498910909 in words is "eighty-one billion, four hundred ninety-eight million, nine hundred ten thousand, nine hundred nine".