21090041 has 8 divisors (see below), whose sum is σ = 24595200. Its totient is φ = 18076884.

The previous prime is 21090007. The next prime is 21090061. The reversal of 21090041 is 14009012.

It is a happy number.

It is not a de Polignac number, because 21090041 - 2¹⁸ = 20827897 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21090061) 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, 30401 + ... + 31086.

It is an arithmetic number, because the mean of its divisors is an integer number (3074400).

Almost surely, 2^21090041 is an apocalyptic number.

It is an amenable number.

21090041 is a deficient number, since it is larger than the sum of its proper divisors (3505159).

21090041 is an frugal number, since it uses more digits than its factorization.

21090041 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 61508 (or 61494 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 17.

The square root of 21090041 is about 4592.3894651913. The cubic root of 21090041 is about 276.2861669921.

Adding to 21090041 its reverse (14009012), we get a palindrome (35099053).

The spelling of 21090041 in words is "twenty-one million, ninety thousand, forty-one".