21211007 has 4 divisors (see below), whose sum is σ = 21253680. Its totient is φ = 21168336.

The previous prime is 21210989. The next prime is 21211009. The reversal of 21211007 is 70011212.

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

It is a cyclic number.

It is not a de Polignac number, because 21211007 - 2¹⁶ = 21145471 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21210982 and 21211000.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21211009) 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, 20582 + ... + 21587.

It is an arithmetic number, because the mean of its divisors is an integer number (5313420).

Almost surely, 2^21211007 is an apocalyptic number.

21211007 is a deficient number, since it is larger than the sum of its proper divisors (42673).

21211007 is an equidigital number, since it uses as much as digits as its factorization.

21211007 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42672.

The product of its (nonzero) digits is 28, while the sum is 14.

The square root of 21211007 is about 4605.5409020005. The cubic root of 21211007 is about 276.8133911502.

Adding to 21211007 its reverse (70011212), we get a palindrome (91222219).

The spelling of 21211007 in words is "twenty-one million, two hundred eleven thousand, seven".