21021541 has 8 divisors (see below), whose sum is σ = 21337344. Its totient is φ = 20708160.

The previous prime is 21021529. The next prime is 21021569. The reversal of 21021541 is 14512012.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21021541 - 2²³ = 12632933 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 (21022541) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 23421 + ... + 24301.

It is an arithmetic number, because the mean of its divisors is an integer number (2667168).

Almost surely, 2^21021541 is an apocalyptic number.

It is an amenable number.

21021541 is a deficient number, since it is larger than the sum of its proper divisors (315803).

21021541 is a wasteful number, since it uses less digits than its factorization.

21021541 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1211.

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

The square root of 21021541 is about 4584.9254083355. The cubic root of 21021541 is about 275.9867187126.

Adding to 21021541 its reverse (14512012), we get a palindrome (35533553).

The spelling of 21021541 in words is "twenty-one million, twenty-one thousand, five hundred forty-one".