21110021010 has 128 divisors (see below), whose sum is σ = 61454856960. Its totient is φ = 5125068288.

The previous prime is 21110020979. The next prime is 21110021017. The reversal of 21110021010 is 1012001112.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21110020983 and 21110021001.

It is not an unprimeable number, because it can be changed into a prime (21110021017) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 215037 + ... + 297423.

It is an arithmetic number, because the mean of its divisors is an integer number (480116070).

Almost surely, 2^21110021010 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21110021010, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30727428480).

21110021010 is an abundant number, since it is smaller than the sum of its proper divisors (40344835950).

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

21110021010 is a wasteful number, since it uses less digits than its factorization.

21110021010 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 82489 (or 82483 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 9.

Adding to 21110021010 its reverse (1012001112), we get a palindrome (22122022122).

The spelling of 21110021010 in words is "twenty-one billion, one hundred ten million, twenty-one thousand, ten".