21620041 has 4 divisors (see below), whose sum is σ = 21818500. Its totient is φ = 21421584.

The previous prime is 21620021. The next prime is 21620059. The reversal of 21620041 is 14002612.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 19324816 + 2295225 = 4396^2 + 1515^2 .

It is a cyclic number.

It is not a de Polignac number, because 21620041 - 2¹⁵ = 21587273 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21619997 and 21620024.

It is not an unprimeable number, because it can be changed into a prime (21620021) 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, 99066 + ... + 99283.

It is an arithmetic number, because the mean of its divisors is an integer number (5454625).

Almost surely, 2^21620041 is an apocalyptic number.

It is an amenable number.

21620041 is a deficient number, since it is larger than the sum of its proper divisors (198459).

21620041 is a wasteful number, since it uses less digits than its factorization.

21620041 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 198458.

The product of its (nonzero) digits is 96, while the sum is 16.

The square root of 21620041 is about 4649.7355838800. The cubic root of 21620041 is about 278.5814349494.

Adding to 21620041 its reverse (14002612), we get a palindrome (35622653).

The spelling of 21620041 in words is "twenty-one million, six hundred twenty thousand, forty-one".