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 a brilliant number, because the two primes have the same length.
It is a cyclic number.
It is a de Polignac number, because none of the positive numbers 2k-1541 is a prime.
It is a Duffinian number.
It is a Curzon number.
It is a nialpdrome in base 7 and base 12.
It is a congruent number.
It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 1541.
21541 is an apocalyptic number.
1541 is the 23-rd octagonal number.
It is an amenable number.
1541 is an equidigital number, since it uses as much as digits as its factorization.
1541 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 90.
The square root of 1541 is about 39.2555728528. The cubic root of 1541 is about 11.5505025299.
Subtracting from 1541 its product of digits (20), we obtain a square (1521 = 392).
Adding to 1541 its reverse (1451), we get a palindrome (2992).
The spelling of 1541 in words is "one thousand, five hundred forty-one".