21555300404 has 24 divisors (see below), whose sum is σ = 41156623200. Its totient is φ = 9796531680.

The previous prime is 21555300359. The next prime is 21555300449. The reversal of 21555300404 is 40400355512.

It is an interprime number because it is at equal distance from previous prime (21555300359) and next prime (21555300449).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 341342 + ... + 399530.

It is an arithmetic number, because the mean of its divisors is an integer number (1714859300).

Almost surely, 2^21555300404 is an apocalyptic number.

It is an amenable number.

21555300404 is a deficient number, since it is larger than the sum of its proper divisors (19601322796).

21555300404 is a wasteful number, since it uses less digits than its factorization.

21555300404 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 66623 (or 66621 counting only the distinct ones).

The product of its (nonzero) digits is 12000, while the sum is 29.

Adding to 21555300404 its reverse (40400355512), we get a palindrome (61955655916).

The spelling of 21555300404 in words is "twenty-one billion, five hundred fifty-five million, three hundred thousand, four hundred four".