21100412 has 12 divisors (see below), whose sum is σ = 38869320. Its totient is φ = 9994896.

The previous prime is 21100411. The next prime is 21100423. The reversal of 21100412 is 21400112.

It is a junction number, because it is equal to n+sod(n) for n = 21100393 and 21100402.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21100411) 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, 138743 + ... + 138894.

It is an arithmetic number, because the mean of its divisors is an integer number (3239110).

Almost surely, 2^21100412 is an apocalyptic number.

It is an amenable number.

21100412 is a deficient number, since it is larger than the sum of its proper divisors (17768908).

21100412 is a wasteful number, since it uses less digits than its factorization.

21100412 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 277660 (or 277658 counting only the distinct ones).

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

The square root of 21100412 is about 4593.5184771589. The cubic root of 21100412 is about 276.3314473574.

Adding to 21100412 its reverse (21400112), we get a palindrome (42500524).

It can be divided in two parts, 21100 and 412, that added together give a palindrome (21512).

The spelling of 21100412 in words is "twenty-one million, one hundred thousand, four hundred twelve".