21221021010 has 128 divisors (see below), whose sum is σ = 58873651200. Its totient is φ = 4795234560.

The previous prime is 21221020999. The next prime is 21221021011. The reversal of 21221021010 is 1012012212.

It is a super-2 number, since 2×21221021010² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21221021011) 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, 6802231 + ... + 6805349.

It is an arithmetic number, because the mean of its divisors is an integer number (459950400).

Almost surely, 2^21221021010 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21221021010, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29436825600).

21221021010 is an abundant number, since it is smaller than the sum of its proper divisors (37652630190).

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

21221021010 is a wasteful number, since it uses less digits than its factorization.

21221021010 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3496.

The product of its (nonzero) digits is 16, while the sum is 12.

Adding to 21221021010 its reverse (1012012212), we get a palindrome (22233033222).

The spelling of 21221021010 in words is "twenty-one billion, two hundred twenty-one million, twenty-one thousand, ten".