21201541 has 4 divisors (see below), whose sum is σ = 21210784. Its totient is φ = 21192300.

The previous prime is 21201539. The next prime is 21201553. The reversal of 21201541 is 14510212.

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 not a de Polignac number, because 21201541 - 2¹ = 21201539 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 (21201041) 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, 1726 + ... + 6736.

It is an arithmetic number, because the mean of its divisors is an integer number (5302696).

Almost surely, 2^21201541 is an apocalyptic number.

It is an amenable number.

21201541 is a deficient number, since it is larger than the sum of its proper divisors (9243).

21201541 is an equidigital number, since it uses as much as digits as its factorization.

21201541 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9242.

The product of its (nonzero) digits is 80, while the sum is 16.

The square root of 21201541 is about 4604.5131121542. The cubic root of 21201541 is about 276.7722064727.

Adding to 21201541 its reverse (14510212), we get a palindrome (35711753).

The spelling of 21201541 in words is "twenty-one million, two hundred one thousand, five hundred forty-one".