81003501 has 24 divisors (see below), whose sum is σ = 119595840. Its totient is φ = 52819776.

The previous prime is 81003463. The next prime is 81003509. The reversal of 81003501 is 10530018.

It is a happy number.

It is not a de Polignac number, because 81003501 - 2⁶ = 81003437 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81003509) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 90880 + ... + 91766.

It is an arithmetic number, because the mean of its divisors is an integer number (4983160).

Almost surely, 2^81003501 is an apocalyptic number.

It is an amenable number.

81003501 is a deficient number, since it is larger than the sum of its proper divisors (38592339).

81003501 is a wasteful number, since it uses less digits than its factorization.

81003501 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1105 (or 1102 counting only the distinct ones).

The product of its (nonzero) digits is 120, while the sum is 18.

The square root of 81003501 is about 9000.1944978984. The cubic root of 81003501 is about 432.6811047256.

Adding to 81003501 its reverse (10530018), we get a palindrome (91533519).

The spelling of 81003501 in words is "eighty-one million, three thousand, five hundred one".