21204002240 has 28 divisors (see below), whose sum is σ = 50492031096. Its totient is φ = 8481600768.

The previous prime is 21204002231. The next prime is 21204002257. The reversal of 21204002240 is 4220040212.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 33130934 + ... + 33131573.

Almost surely, 2^21204002240 is an apocalyptic number.

21204002240 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21204002240 is an abundant number, since it is smaller than the sum of its proper divisors (29288028856).

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

21204002240 is an equidigital number, since it uses as much as digits as its factorization.

21204002240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 66262524 (or 66262514 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 17.

Adding to 21204002240 its reverse (4220040212), we get a palindrome (25424042452).

The spelling of 21204002240 in words is "twenty-one billion, two hundred four million, two thousand, two hundred forty".