21012010 has 16 divisors (see below), whose sum is σ = 38248200. Its totient is φ = 8310016.

The previous prime is 21011981. The next prime is 21012053. The reversal of 21012010 is 1021012.

It can be written as a sum of positive squares in 4 ways, for example, as 9715689 + 11296321 = 3117^2 + 3361^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21011984 and 21012002.

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, 10915 + ... + 12694.

Almost surely, 2^21012010 is an apocalyptic number.

21012010 is a deficient number, since it is larger than the sum of its proper divisors (17236190).

21012010 is a wasteful number, since it uses less digits than its factorization.

21012010 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23705.

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

The square root of 21012010 is about 4583.8859060845. The cubic root of 21012010 is about 275.9450023440.

Adding to 21012010 its reverse (1021012), we get a palindrome (22033022).

The spelling of 21012010 in words is "twenty-one million, twelve thousand, ten".