21121210010 has 16 divisors (see below), whose sum is σ = 38181350376. Its totient is φ = 8412223488.

The previous prime is 21121210007. The next prime is 21121210037. The reversal of 21121210010 is 1001212112.

It can be written as a sum of positive squares in 4 ways, for example, as 19678197841 + 1443012169 = 140279^2 + 37987^2 .

It is a super-2 number, since 2×21121210010² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21121209973 and 21121210000.

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, 4530119 + ... + 4534778.

Almost surely, 2^21121210010 is an apocalyptic number.

21121210010 is a deficient number, since it is larger than the sum of its proper divisors (17060140366).

21121210010 is a wasteful number, since it uses less digits than its factorization.

21121210010 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9065137.

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

Adding to 21121210010 its reverse (1001212112), we get a palindrome (22122422122).

The spelling of 21121210010 in words is "twenty-one billion, one hundred twenty-one million, two hundred ten thousand, ten".