21011541 has 8 divisors (see below), whose sum is σ = 29663424. Its totient is φ = 13183680.

The previous prime is 21011539. The next prime is 21011567. The reversal of 21011541 is 14511012.

It is a happy number.

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

It is not a de Polignac number, because 21011541 - 2¹ = 21011539 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21011541.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21011531) 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, 205945 + ... + 206046.

It is an arithmetic number, because the mean of its divisors is an integer number (3707928).

Almost surely, 2^21011541 is an apocalyptic number.

It is an amenable number.

21011541 is a deficient number, since it is larger than the sum of its proper divisors (8651883).

21011541 is a wasteful number, since it uses less digits than its factorization.

21011541 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 412011.

The product of its (nonzero) digits is 40, while the sum is 15.

The square root of 21011541 is about 4583.8347483303. The cubic root of 21011541 is about 275.9429492457.

Adding to 21011541 its reverse (14511012), we get a palindrome (35522553).

The spelling of 21011541 in words is "twenty-one million, eleven thousand, five hundred forty-one".