81950609 has 8 divisors (see below), whose sum is σ = 88352040. Its totient is φ = 75563136.

The previous prime is 81950593. The next prime is 81950641. The reversal of 81950609 is 90605918.

It can be written as a sum of positive squares in 4 ways, for example, as 14250625 + 67699984 = 3775^2 + 8228^2 .

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 81950609 - 2⁴ = 81950593 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81950689) 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, 10949 + ... + 16845.

It is an arithmetic number, because the mean of its divisors is an integer number (11044005).

Almost surely, 2^81950609 is an apocalyptic number.

It is an amenable number.

81950609 is a deficient number, since it is larger than the sum of its proper divisors (6401431).

81950609 is a wasteful number, since it uses less digits than its factorization.

81950609 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6979.

The product of its (nonzero) digits is 19440, while the sum is 38.

The square root of 81950609 is about 9052.6575655992. The cubic root of 81950609 is about 434.3609041127.

The spelling of 81950609 in words is "eighty-one million, nine hundred fifty thousand, six hundred nine".