21645002 has 8 divisors (see below), whose sum is σ = 32765700. Its totient is φ = 10723104.

The previous prime is 21644969. The next prime is 21645023. The reversal of 21645002 is 20054612.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 17230801 + 4414201 = 4151^2 + 2101^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a super-2 number, since 2×21645002² = 937012223160008, which contains 22 as substring.

It is an unprimeable number.

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 in 3 ways as a sum of consecutive naturals, for example, 49427 + ... + 49862.

Almost surely, 2^21645002 is an apocalyptic number.

21645002 is a deficient number, since it is larger than the sum of its proper divisors (11120698).

21645002 is a wasteful number, since it uses less digits than its factorization.

21645002 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 99400.

The product of its (nonzero) digits is 480, while the sum is 20.

The square root of 21645002 is about 4652.4189407232. The cubic root of 21645002 is about 278.6886039851.

Adding to 21645002 its reverse (20054612), we get a palindrome (41699614).

The spelling of 21645002 in words is "twenty-one million, six hundred forty-five thousand, two".