21305002 has 4 divisors (see below), whose sum is σ = 31957506. Its totient is φ = 10652500.

The previous prime is 21304991. The next prime is 21305003. The reversal of 21305002 is 20050312.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 21261321 + 43681 = 4611^2 + 209^2 .

It is a super-2 number, since 2×21305002² = 907806220440008, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21305003) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5326249 + ... + 5326252.

Almost surely, 2^21305002 is an apocalyptic number.

21305002 is a deficient number, since it is larger than the sum of its proper divisors (10652504).

21305002 is a wasteful number, since it uses less digits than its factorization.

21305002 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10652503.

The product of its (nonzero) digits is 60, while the sum is 13.

The square root of 21305002 is about 4615.7341777880. The cubic root of 21305002 is about 277.2216812922.

Adding to 21305002 its reverse (20050312), we get a palindrome (41355314).

The spelling of 21305002 in words is "twenty-one million, three hundred five thousand, two".