21002011 has 8 divisors (see below), whose sum is σ = 22312400. Its totient is φ = 19712160.

The previous prime is 21001991. The next prime is 21002039. The reversal of 21002011 is 11020012.

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

It is a cyclic number.

It is not a de Polignac number, because 21002011 - 2⁵ = 21001979 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21001985 and 21002003.

It is not an unprimeable number, because it can be changed into a prime (21002081) 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, 3000 + ... + 7141.

It is an arithmetic number, because the mean of its divisors is an integer number (2789050).

Almost surely, 2^21002011 is an apocalyptic number.

21002011 is a deficient number, since it is larger than the sum of its proper divisors (1310389).

21002011 is a wasteful number, since it uses less digits than its factorization.

21002011 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10269.

The product of its (nonzero) digits is 4, while the sum is 7.

The square root of 21002011 is about 4582.7951077918. The cubic root of 21002011 is about 275.9012240182.

Adding to 21002011 its reverse (11020012), we get a palindrome (32022023).

The spelling of 21002011 in words is "twenty-one million, two thousand, eleven".