21010012 has 12 divisors (see below), whose sum is σ = 36923040. Its totient is φ = 10460576.

The previous prime is 21009997. The next prime is 21010013. The reversal of 21010012 is 21001012.

It is a junction number, because it is equal to n+sod(n) for n = 21009977 and 21010004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21010013) 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, 10033 + ... + 11944.

It is an arithmetic number, because the mean of its divisors is an integer number (3076920).

Almost surely, 2^21010012 is an apocalyptic number.

It is an amenable number.

21010012 is a deficient number, since it is larger than the sum of its proper divisors (15913028).

21010012 is a wasteful number, since it uses less digits than its factorization.

21010012 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22220 (or 22218 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 7.

The square root of 21010012 is about 4583.6679635419. The cubic root of 21010012 is about 275.9362556703.

Adding to 21010012 its reverse (21001012), we get a palindrome (42011024).

The spelling of 21010012 in words is "twenty-one million, ten thousand, twelve".