81023565 has 16 divisors (see below), whose sum is σ = 148157568. Its totient is φ = 37039296.

The previous prime is 81023563. The next prime is 81023573. The reversal of 81023565 is 56532018.

It is not a de Polignac number, because 81023565 - 2¹ = 81023563 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81023561) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 385722 + ... + 385931.

It is an arithmetic number, because the mean of its divisors is an integer number (9259848).

Almost surely, 2^81023565 is an apocalyptic number.

It is an amenable number.

81023565 is a deficient number, since it is larger than the sum of its proper divisors (67134003).

81023565 is a wasteful number, since it uses less digits than its factorization.

81023565 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 771668.

The product of its (nonzero) digits is 7200, while the sum is 30.

The square root of 81023565 is about 9001.3090714629. The cubic root of 81023565 is about 432.7168258031.

The spelling of 81023565 in words is "eighty-one million, twenty-three thousand, five hundred sixty-five".