21818002 has 4 divisors (see below), whose sum is σ = 32727006. Its totient is φ = 10909000.

The previous prime is 21817981. The next prime is 21818003. The reversal of 21818002 is 20081812.

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., 11964681 + 9853321 = 3459^2 + 3139^2 .

It is a super-2 number, since 2×21818002² = 952050422544008, which contains 22 as substring.

It is a Smith number, since the sum of its digits (22) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (21818003) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5454499 + ... + 5454502.

Almost surely, 2^21818002 is an apocalyptic number.

21818002 is a deficient number, since it is larger than the sum of its proper divisors (10909004).

21818002 is a wasteful number, since it uses less digits than its factorization.

21818002 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10909003.

The product of its (nonzero) digits is 256, while the sum is 22.

The square root of 21818002 is about 4670.9744165431. The cubic root of 21818002 is about 279.4291174501.

Adding to 21818002 its reverse (20081812), we get a palindrome (41899814).

The spelling of 21818002 in words is "twenty-one million, eight hundred eighteen thousand, two".