21012101010 has 96 divisors (see below), whose sum is σ = 56452930560. Its totient is φ = 5416790400.

The previous prime is 21012101009. The next prime is 21012101027. The reversal of 21012101010 is 1010121012.

It is a happy number.

21012101010 is an esthetic number in base 10, because in such base its adjacent digits differ by 1.

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

It is an alternating number because its digits alternate between even and odd.

It is a junction number, because it is equal to n+sod(n) for n = 21012100983 and 21012101001.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 3090715 + ... + 3097505.

It is an arithmetic number, because the mean of its divisors is an integer number (588051360).

Almost surely, 2^21012101010 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21012101010, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28226465280).

21012101010 is an abundant number, since it is smaller than the sum of its proper divisors (35440829550).

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

21012101010 is a wasteful number, since it uses less digits than its factorization.

21012101010 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7944 (or 7941 counting only the distinct ones).

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

Adding to 21012101010 its reverse (1010121012), we get a palindrome (22022222022).

The spelling of 21012101010 in words is "twenty-one billion, twelve million, one hundred one thousand, ten".