81503575 has 6 divisors (see below), whose sum is σ = 101064464. Its totient is φ = 65202840.

The previous prime is 81503537. The next prime is 81503579. The reversal of 81503575 is 57530518.

It is not a de Polignac number, because 81503575 - 2¹⁷ = 81372503 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 81503575.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81503579) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1630047 + ... + 1630096.

Almost surely, 2^81503575 is an apocalyptic number.

81503575 is a deficient number, since it is larger than the sum of its proper divisors (19560889).

81503575 is a wasteful number, since it uses less digits than its factorization.

81503575 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3260153 (or 3260148 counting only the distinct ones).

The product of its (nonzero) digits is 21000, while the sum is 34.

The square root of 81503575 is about 9027.9330413999. The cubic root of 81503575 is about 433.5696623445.

The spelling of 81503575 in words is "eighty-one million, five hundred three thousand, five hundred seventy-five".