73131809 has 4 divisors (see below), whose sum is σ = 73211460. Its totient is φ = 73052160.

The previous prime is 73131803. The next prime is 73131811. The reversal of 73131809 is 90813137.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 17405584 + 55726225 = 4172^2 + 7465^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-73131809 is a prime.

It is a super-2 number, since 2×73131809² = 10696522975224962, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (73131803) 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, 38432 + ... + 40289.

It is an arithmetic number, because the mean of its divisors is an integer number (18302865).

Almost surely, 2^73131809 is an apocalyptic number.

It is an amenable number.

73131809 is a deficient number, since it is larger than the sum of its proper divisors (79651).

73131809 is an equidigital number, since it uses as much as digits as its factorization.

73131809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 79650.

The product of its (nonzero) digits is 4536, while the sum is 32.

The square root of 73131809 is about 8551.7138048464. The cubic root of 73131809 is about 418.1853092723.

The spelling of 73131809 in words is "seventy-three million, one hundred thirty-one thousand, eight hundred nine".