21221002 has 16 divisors (see below), whose sum is σ = 35316000. Its totient is φ = 9481840.

The previous prime is 21220993. The next prime is 21221003. The reversal of 21221002 is 20012212.

It is a self number, because there is not a number n which added to its sum of digits gives 21221002.

It is not an unprimeable number, because it can be changed into a prime (21221003) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6877 + ... + 9472.

It is an arithmetic number, because the mean of its divisors is an integer number (2207250).

Almost surely, 2^21221002 is an apocalyptic number.

21221002 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

21221002 is a deficient number, since it is larger than the sum of its proper divisors (14094998).

21221002 is a wasteful number, since it uses less digits than its factorization.

21221002 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16421.

The product of its (nonzero) digits is 16, while the sum is 10.

The square root of 21221002 is about 4606.6258801861. The cubic root of 21221002 is about 276.8568641040.

Adding to 21221002 its reverse (20012212), we get a palindrome (41233214).

The spelling of 21221002 in words is "twenty-one million, two hundred twenty-one thousand, two".