21221001010 has 64 divisors (see below), whose sum is σ = 43928438400. Its totient is φ = 7299763200.

The previous prime is 21221001007. The next prime is 21221001017. The reversal of 21221001010 is 1010012212.

It is a Harshad number since it is a multiple of its sum of digits (10).

It is not an unprimeable number, because it can be changed into a prime (21221001017) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1474650 + ... + 1488970.

It is an arithmetic number, because the mean of its divisors is an integer number (686381850).

Almost surely, 2^21221001010 is an apocalyptic number.

21221001010 is an abundant number, since it is smaller than the sum of its proper divisors (22707437390).

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

21221001010 is a wasteful number, since it uses less digits than its factorization.

21221001010 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15067.

The product of its (nonzero) digits is 8, while the sum is 10.

Adding to 21221001010 its reverse (1010012212), we get a palindrome (22231013222).

The spelling of 21221001010 in words is "twenty-one billion, two hundred twenty-one million, one thousand, ten".