21421012 has 24 divisors (see below), whose sum is σ = 38455200. Its totient is φ = 10437216.

The previous prime is 21420991. The next prime is 21421051. The reversal of 21421012 is 21012412.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 21420983 and 21421001.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 32478 + ... + 33130.

It is an arithmetic number, because the mean of its divisors is an integer number (1602300).

Almost surely, 2^21421012 is an apocalyptic number.

It is an amenable number.

21421012 is a deficient number, since it is larger than the sum of its proper divisors (17034188).

21421012 is a wasteful number, since it uses less digits than its factorization.

21421012 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 855 (or 853 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 13.

The square root of 21421012 is about 4628.2839152325. The cubic root of 21421012 is about 277.7239465938.

Adding to 21421012 its reverse (21012412), we get a palindrome (42433424).

The spelling of 21421012 in words is "twenty-one million, four hundred twenty-one thousand, twelve".