21001412 has 6 divisors (see below), whose sum is σ = 36752478. Its totient is φ = 10500704.

The previous prime is 21001411. The next prime is 21001417. The reversal of 21001412 is 21410012.

It can be written as a sum of positive squares in only one way, i.e., 13957696 + 7043716 = 3736^2 + 2654^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21001393 and 21001402.

It is not an unprimeable number, because it can be changed into a prime (21001411) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2625173 + ... + 2625180.

It is an arithmetic number, because the mean of its divisors is an integer number (6125413).

Almost surely, 2^21001412 is an apocalyptic number.

It is an amenable number.

21001412 is a deficient number, since it is larger than the sum of its proper divisors (15751066).

21001412 is a wasteful number, since it uses less digits than its factorization.

21001412 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5250357 (or 5250355 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 11.

The square root of 21001412 is about 4582.7297541967. The cubic root of 21001412 is about 275.8986009931.

Adding to 21001412 its reverse (21410012), we get a palindrome (42411424).

The spelling of 21001412 in words is "twenty-one million, one thousand, four hundred twelve".