73646561 has 4 divisors (see below), whose sum is σ = 74655492. Its totient is φ = 72637632.

The previous prime is 73646557. The next prime is 73646609. The reversal of 73646561 is 16564637.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 16564637 = 19 ⋅871823.

It can be written as a sum of positive squares in 2 ways, for example, as 63123025 + 10523536 = 7945^2 + 3244^2 .

It is a cyclic number.

It is not a de Polignac number, because 73646561 - 2² = 73646557 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (73646501) 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, 504356 + ... + 504501.

It is an arithmetic number, because the mean of its divisors is an integer number (18663873).

Almost surely, 2^73646561 is an apocalyptic number.

It is an amenable number.

73646561 is a deficient number, since it is larger than the sum of its proper divisors (1008931).

73646561 is a wasteful number, since it uses less digits than its factorization.

73646561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1008930.

The product of its digits is 90720, while the sum is 38.

The square root of 73646561 is about 8581.7574540417. The cubic root of 73646561 is about 419.1641748740.

The spelling of 73646561 in words is "seventy-three million, six hundred forty-six thousand, five hundred sixty-one".