21351412 has 6 divisors (see below), whose sum is σ = 37364978. Its totient is φ = 10675704.

The previous prime is 21351401. The next prime is 21351413. The reversal of 21351412 is 21415312.

It can be written as a sum of positive squares in only one way, i.e., 17943696 + 3407716 = 4236^2 + 1846^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21351412.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21351413) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2668923 + ... + 2668930.

Almost surely, 2^21351412 is an apocalyptic number.

It is an amenable number.

21351412 is a deficient number, since it is larger than the sum of its proper divisors (16013566).

21351412 is a wasteful number, since it uses less digits than its factorization.

21351412 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5337857 (or 5337855 counting only the distinct ones).

The product of its digits is 240, while the sum is 19.

The square root of 21351412 is about 4620.7588121433. The cubic root of 21351412 is about 277.4228316661.

Adding to 21351412 its reverse (21415312), we get a palindrome (42766724).

The spelling of 21351412 in words is "twenty-one million, three hundred fifty-one thousand, four hundred twelve".