21511041 has 16 divisors (see below), whose sum is σ = 29198400. Its totient is φ = 14084928.

The previous prime is 21511031. The next prime is 21511079. The reversal of 21511041 is 14011512.

It is a happy number.

It is not a de Polignac number, because 21511041 - 2⁶ = 21510977 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21511041.

It is not an unprimeable number, because it can be changed into a prime (21511031) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 51130 + ... + 51548.

It is an arithmetic number, because the mean of its divisors is an integer number (1824900).

Almost surely, 2^21511041 is an apocalyptic number.

It is an amenable number.

21511041 is a deficient number, since it is larger than the sum of its proper divisors (7687359).

21511041 is a wasteful number, since it uses less digits than its factorization.

21511041 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 688.

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

The square root of 21511041 is about 4637.9996765847. Note that the first 3 decimals coincide. The cubic root of 21511041 is about 278.1124788539.

Adding to 21511041 its reverse (14011512), we get a palindrome (35522553).

The spelling of 21511041 in words is "twenty-one million, five hundred eleven thousand, forty-one".