15501 has 4 divisors (see below), whose sum is σ = 20672. Its totient is φ = 10332.

The previous prime is 15497. The next prime is 15511. The reversal of 15501 is 10551.

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, and also an emirpimes, since its reverse is a distinct semiprime: 10551 = 3 ⋅3517.

It is not a de Polignac number, because 15501 - 2² = 15497 is a prime.

It is a D-number.

It is the 125-th Hogben number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (15511) by changing a digit.

It is a nontrivial repunit in base 124.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2581 + ... + 2586.

It is an arithmetic number, because the mean of its divisors is an integer number (5168).

2¹⁵⁵⁰¹ is an apocalyptic number.

It is an amenable number.

15501 is a deficient number, since it is larger than the sum of its proper divisors (5171).

15501 is an equidigital number, since it uses as much as digits as its factorization.

15501 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5170.

The product of its (nonzero) digits is 25, while the sum is 12.

The square root of 15501 is about 124.5030120118. The cubic root of 15501 is about 24.9336909465.

Subtracting from 15501 its reverse (10551), we obtain a triangular number (4950 = T₉₉).

It can be divided in two parts, 1550 and 1, that added together give a palindrome (1551).

The spelling of 15501 in words is "fifteen thousand, five hundred one".