81501501 has 4 divisors (see below), whose sum is σ = 108668672. Its totient is φ = 54334332.

The previous prime is 81501499. The next prime is 81501503. The reversal of 81501501 is 10510518.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is an interprime number because it is at equal distance from previous prime (81501499) and next prime (81501503).

It is not a de Polignac number, because 81501501 - 2¹ = 81501499 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81501503) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13583581 + ... + 13583586.

It is an arithmetic number, because the mean of its divisors is an integer number (27167168).

Almost surely, 2^81501501 is an apocalyptic number.

It is an amenable number.

81501501 is a deficient number, since it is larger than the sum of its proper divisors (27167171).

81501501 is a wasteful number, since it uses less digits than its factorization.

81501501 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27167170.

The product of its (nonzero) digits is 200, while the sum is 21.

The square root of 81501501 is about 9027.8181749524. The cubic root of 81501501 is about 433.5659846690.

The spelling of 81501501 in words is "eighty-one million, five hundred one thousand, five hundred one".