21137211 has 6 divisors (see below), whose sum is σ = 30531540. Its totient is φ = 14091468.

The previous prime is 21137191. The next prime is 21137231. The reversal of 21137211 is 11273112.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21137191) and next prime (21137231).

It is not a de Polignac number, because 21137211 - 2¹⁰ = 21136187 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21137231) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1174281 + ... + 1174298.

It is an arithmetic number, because the mean of its divisors is an integer number (5088590).

Almost surely, 2^21137211 is an apocalyptic number.

21137211 is a deficient number, since it is larger than the sum of its proper divisors (9394329).

21137211 is a wasteful number, since it uses less digits than its factorization.

21137211 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2348585 (or 2348582 counting only the distinct ones).

The product of its digits is 84, while the sum is 18.

The square root of 21137211 is about 4597.5222674828. The cubic root of 21137211 is about 276.4919942266.

The spelling of 21137211 in words is "twenty-one million, one hundred thirty-seven thousand, two hundred eleven".