21011020110 has 40 divisors (see below), whose sum is σ = 56496300696. Its totient is φ = 5602938480.

The previous prime is 21011020067. The next prime is 21011020111. The reversal of 21011020110 is 1102011012.

It is a happy number.

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

It is a junction number, because it is equal to n+sod(n) for n = 21011020092 and 21011020101.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21011020111) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 12968956 + ... + 12970575.

Almost surely, 2^21011020110 is an apocalyptic number.

21011020110 is an abundant number, since it is smaller than the sum of its proper divisors (35485280586).

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

21011020110 is a wasteful number, since it uses less digits than its factorization.

21011020110 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25939550 (or 25939541 counting only the distinct ones).

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

Adding to 21011020110 its reverse (1102011012), we get a palindrome (22113031122).

The spelling of 21011020110 in words is "twenty-one billion, eleven million, twenty thousand, one hundred ten".