81525773 has 4 divisors (see below), whose sum is σ = 93172320. Its totient is φ = 69879228.

The previous prime is 81525767. The next prime is 81525779. The reversal of 81525773 is 37752518.

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: 37752518 = 2 ⋅18876259.

It is an interprime number because it is at equal distance from previous prime (81525767) and next prime (81525779).

It is a cyclic number.

It is not a de Polignac number, because 81525773 - 2²⁰ = 80477197 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 (81525779) 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, 5823263 + ... + 5823276.

It is an arithmetic number, because the mean of its divisors is an integer number (23293080).

Almost surely, 2^81525773 is an apocalyptic number.

It is an amenable number.

81525773 is a deficient number, since it is larger than the sum of its proper divisors (11646547).

81525773 is a wasteful number, since it uses less digits than its factorization.

81525773 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11646546.

The product of its digits is 58800, while the sum is 38.

The square root of 81525773 is about 9029.1623642506. The cubic root of 81525773 is about 433.6090205597.

The spelling of 81525773 in words is "eighty-one million, five hundred twenty-five thousand, seven hundred seventy-three".