81503687 has 4 divisors (see below), whose sum is σ = 83237856. Its totient is φ = 79769520.

The previous prime is 81503663. The next prime is 81503689. The reversal of 81503687 is 78630518.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 78630518 = 2 ⋅39315259.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81503687 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 81503687.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81503689) 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, 867014 + ... + 867107.

It is an arithmetic number, because the mean of its divisors is an integer number (20809464).

Almost surely, 2^81503687 is an apocalyptic number.

81503687 is a deficient number, since it is larger than the sum of its proper divisors (1734169).

81503687 is a wasteful number, since it uses less digits than its factorization.

81503687 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1734168.

The product of its (nonzero) digits is 40320, while the sum is 38.

The square root of 81503687 is about 9027.9392443680. The cubic root of 81503687 is about 433.5698609443.

The spelling of 81503687 in words is "eighty-one million, five hundred three thousand, six hundred eighty-seven".