21121121010 has 128 divisors (see below), whose sum is σ = 56234476800. Its totient is φ = 5034368000.

The previous prime is 21121120987. The next prime is 21121121039. The reversal of 21121121010 is 1012112112.

It is a super-2 number, since 2×21121121010² (a number of 21 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 4964044 + ... + 4968296.

It is an arithmetic number, because the mean of its divisors is an integer number (439331850).

Almost surely, 2^21121121010 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21121121010, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28117238400).

21121121010 is an abundant number, since it is smaller than the sum of its proper divisors (35113355790).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21121121010 is a wasteful number, since it uses less digits than its factorization.

21121121010 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4524.

The product of its (nonzero) digits is 8, while the sum is 12.

Adding to 21121121010 its reverse (1012112112), we get a palindrome (22133233122).

It can be divided in two parts, 211211 and 21010, that added together give a triangular number (232221 = T₆₈₁).

The spelling of 21121121010 in words is "twenty-one billion, one hundred twenty-one million, one hundred twenty-one thousand, ten".