21090011 has 8 divisors (see below), whose sum is σ = 22055424. Its totient is φ = 20128680.

The previous prime is 21090007. The next prime is 21090061. The reversal of 21090011 is 11009012.

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

It is not a de Polignac number, because 21090011 - 2² = 21090007 is a prime.

It is a Duffinian 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, 15230 + ... + 16556.

It is an arithmetic number, because the mean of its divisors is an integer number (2756928).

Almost surely, 2^21090011 is an apocalyptic number.

21090011 is a deficient number, since it is larger than the sum of its proper divisors (965413).

21090011 is a wasteful number, since it uses less digits than its factorization.

21090011 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2041.

The product of its (nonzero) digits is 18, while the sum is 14.

The square root of 21090011 is about 4592.3861989166. The cubic root of 21090011 is about 276.2860359889.

Adding to 21090011 its reverse (11009012), we get a palindrome (32099023).

The spelling of 21090011 in words is "twenty-one million, ninety thousand, eleven".