81503387 has 4 divisors (see below), whose sum is σ = 93146736. Its totient is φ = 69860040.

The previous prime is 81503363. The next prime is 81503473. The reversal of 81503387 is 78330518.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 81503387 - 2¹⁸ = 81241243 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81503327) 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, 5821664 + ... + 5821677.

It is an arithmetic number, because the mean of its divisors is an integer number (23286684).

Almost surely, 2^81503387 is an apocalyptic number.

81503387 is a deficient number, since it is larger than the sum of its proper divisors (11643349).

81503387 is a wasteful number, since it uses less digits than its factorization.

81503387 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11643348.

The product of its (nonzero) digits is 20160, while the sum is 35.

The square root of 81503387 is about 9027.9226292653. The cubic root of 81503387 is about 433.5693289801.

The spelling of 81503387 in words is "eighty-one million, five hundred three thousand, three hundred eighty-seven".