21211011 has 32 divisors (see below), whose sum is σ = 33408000. Its totient is φ = 13263264.

The previous prime is 21211009. The next prime is 21211013. The reversal of 21211011 is 11011212.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21211009) and next prime (21211013).

It is not a de Polignac number, because 21211011 - 2¹ = 21211009 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a junction number, because it is equal to n+sod(n) for n = 21210984 and 21211002.

It is not an unprimeable number, because it can be changed into a prime (21211013) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 88630 + ... + 88868.

It is an arithmetic number, because the mean of its divisors is an integer number (1044000).

Almost surely, 2^21211011 is an apocalyptic number.

21211011 is a deficient number, since it is larger than the sum of its proper divisors (12196989).

21211011 is a wasteful number, since it uses less digits than its factorization.

21211011 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 440 (or 434 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 9.

The square root of 21211011 is about 4605.5413362600. The cubic root of 21211011 is about 276.8134085508.

Adding to 21211011 its reverse (11011212), we get a palindrome (32222223).

It can be divided in two parts, 212 and 11011, that multiplied together give a palindrome (2334332).

The spelling of 21211011 in words is "twenty-one million, two hundred eleven thousand, eleven".