81038501 has 4 divisors (see below), whose sum is σ = 81057900. Its totient is φ = 81019104.

The previous prime is 81038497. The next prime is 81038521. The reversal of 81038501 is 10583018.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 10583018 = 2 ⋅5291509.

It can be written as a sum of positive squares in 2 ways, for example, as 6630625 + 74407876 = 2575^2 + 8626^2 .

It is a cyclic number.

It is not a de Polignac number, because 81038501 - 2² = 81038497 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81038521) 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, 566 + ... + 12743.

It is an arithmetic number, because the mean of its divisors is an integer number (20264475).

Almost surely, 2^81038501 is an apocalyptic number.

It is an amenable number.

81038501 is a deficient number, since it is larger than the sum of its proper divisors (19399).

81038501 is a wasteful number, since it uses less digits than its factorization.

81038501 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19398.

The product of its (nonzero) digits is 960, while the sum is 26.

The square root of 81038501 is about 9002.1386903335. The cubic root of 81038501 is about 432.7434133825.

The spelling of 81038501 in words is "eighty-one million, thirty-eight thousand, five hundred one".