21215234 has 8 divisors (see below), whose sum is σ = 31857420. Its totient is φ = 10596096.

The previous prime is 21215231. The next prime is 21215237. The reversal of 21215234 is 43251212.

It is an interprime number because it is at equal distance from previous prime (21215231) and next prime (21215237).

It can be written as a sum of positive squares in 2 ways, for example, as 16605625 + 4609609 = 4075^2 + 2147^2 .

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

It is not an unprimeable number, because it can be changed into a prime (21215231) 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, 3239 + ... + 7274.

Almost surely, 2^21215234 is an apocalyptic number.

21215234 is a deficient number, since it is larger than the sum of its proper divisors (10642186).

21215234 is a wasteful number, since it uses less digits than its factorization.

21215234 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11524.

The product of its digits is 480, while the sum is 20.

The square root of 21215234 is about 4605.9997828919. Note that the first 3 decimals coincide. The cubic root of 21215234 is about 276.8317780265.

Adding to 21215234 its reverse (43251212), we get a palindrome (64466446).

The spelling of 21215234 in words is "twenty-one million, two hundred fifteen thousand, two hundred thirty-four".