21212276 has 6 divisors (see below), whose sum is σ = 37121490. Its totient is φ = 10606136.

The previous prime is 21212273. The next prime is 21212281. The reversal of 21212276 is 67221212.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 13868176 + 7344100 = 3724^2 + 2710^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21212273) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2651531 + ... + 2651538.

It is an arithmetic number, because the mean of its divisors is an integer number (6186915).

Almost surely, 2^21212276 is an apocalyptic number.

It is an amenable number.

21212276 is a deficient number, since it is larger than the sum of its proper divisors (15909214).

21212276 is a wasteful number, since it uses less digits than its factorization.

21212276 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5303073 (or 5303071 counting only the distinct ones).

The product of its digits is 672, while the sum is 23.

The square root of 21212276 is about 4605.6786687740. The cubic root of 21212276 is about 276.8189113846.

Adding to 21212276 its reverse (67221212), we get a palindrome (88433488).

The spelling of 21212276 in words is "twenty-one million, two hundred twelve thousand, two hundred seventy-six".