21210121111010 has 16 divisors (see below), whose sum is σ = 41115004000056. Its totient is φ = 7831429333248.

The previous prime is 21210121111007. The next prime is 21210121111061. The reversal of 21210121111010 is 1011112101212.

It can be written as a sum of positive squares in 4 ways, for example, as 18859225683841 + 2350895427169 = 4342721^2 + 1533263^2 .

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, 81577388759 + ... + 81577389018.

Almost surely, 2^{21210121111010} is an apocalyptic number.

21210121111010 is a deficient number, since it is larger than the sum of its proper divisors (19904882889046).

21210121111010 is a wasteful number, since it uses less digits than its factorization.

21210121111010 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 163154777797.

The product of its (nonzero) digits is 8, while the sum is 14.

Adding to 21210121111010 its reverse (1011112101212), we get a palindrome (22221233212222).

The spelling of 21210121111010 in words is "twenty-one trillion, two hundred ten billion, one hundred twenty-one million, one hundred eleven thousand, ten".