21011021210 has 64 divisors (see below), whose sum is σ = 38664410400. Its totient is φ = 8219430912.

The previous prime is 21011021197. The next prime is 21011021261. The reversal of 21011021210 is 1212011012.

It can be written as a sum of positive squares in 16 ways, for example, as 14813080681 + 6197940529 = 121709^2 + 78727^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21011021191 and 21011021200.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 51371486 + ... + 51371894.

Almost surely, 2^21011021210 is an apocalyptic number.

21011021210 is a deficient number, since it is larger than the sum of its proper divisors (17653389190).

21011021210 is a wasteful number, since it uses less digits than its factorization.

21011021210 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 995.

The product of its (nonzero) digits is 8, while the sum is 11.

Adding to 21011021210 its reverse (1212011012), we get a palindrome (22223032222).

The spelling of 21011021210 in words is "twenty-one billion, eleven million, twenty-one thousand, two hundred ten".