21802004 has 12 divisors (see below), whose sum is σ = 43604064. Its totient is φ = 9343704.

The previous prime is 21801943. The next prime is 21802009. The reversal of 21802004 is 40020812.

21802004 is an admirable number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21802009) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 389294 + ... + 389349.

It is an arithmetic number, because the mean of its divisors is an integer number (3633672).

Almost surely, 2^21802004 is an apocalyptic number.

It is an amenable number.

21802004 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

21802004 is a wasteful number, since it uses less digits than its factorization.

21802004 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 778654 (or 778652 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 17.

The square root of 21802004 is about 4669.2616118611. The cubic root of 21802004 is about 279.3608038303.

Adding to 21802004 its reverse (40020812), we get a palindrome (61822816).

The spelling of 21802004 in words is "twenty-one million, eight hundred two thousand, four".