21515041 has 4 divisors (see below), whose sum is σ = 21577392. Its totient is φ = 21452692.

The previous prime is 21515017. The next prime is 21515057. The reversal of 21515041 is 14051512.

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.

It is a cyclic number.

It is not a de Polignac number, because 21515041 - 2⁵ = 21515009 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21515341) 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, 30655 + ... + 31348.

It is an arithmetic number, because the mean of its divisors is an integer number (5394348).

Almost surely, 2^21515041 is an apocalyptic number.

It is an amenable number.

21515041 is a deficient number, since it is larger than the sum of its proper divisors (62351).

21515041 is an equidigital number, since it uses as much as digits as its factorization.

21515041 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 62350.

The product of its (nonzero) digits is 200, while the sum is 19.

The square root of 21515041 is about 4638.4308769238. The cubic root of 21515041 is about 278.1297162185.

Adding to 21515041 its reverse (14051512), we get a palindrome (35566553).

The spelling of 21515041 in words is "twenty-one million, five hundred fifteen thousand, forty-one".