81634417 has 4 divisors (see below), whose sum is σ = 81824256. Its totient is φ = 81444580.

The previous prime is 81634387. The next prime is 81634433. The reversal of 81634417 is 71443618.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 71443618 = 2 ⋅35721809.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81634417 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81634517) 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, 94273 + ... + 95134.

It is an arithmetic number, because the mean of its divisors is an integer number (20456064).

Almost surely, 2^81634417 is an apocalyptic number.

It is an amenable number.

81634417 is a deficient number, since it is larger than the sum of its proper divisors (189839).

81634417 is a wasteful number, since it uses less digits than its factorization.

81634417 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 189838.

The product of its digits is 16128, while the sum is 34.

The square root of 81634417 is about 9035.1766446484. The cubic root of 81634417 is about 433.8015490728.

The spelling of 81634417 in words is "eighty-one million, six hundred thirty-four thousand, four hundred seventeen".