21100004550 has 48 divisors (see below), whose sum is σ = 58142238480. Its totient is φ = 5626667520.

The previous prime is 21100004543. The next prime is 21100004557. The reversal of 21100004550 is 5540000112.

21100004550 is a `hidden beast` number, since 2 + 110 + 0 + 0 + 0 + 4 + 550 = 666.

It is an interprime number because it is at equal distance from previous prime (21100004543) and next prime (21100004557).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21100004557) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 7813467 + ... + 7816166.

It is an arithmetic number, because the mean of its divisors is an integer number (1211296635).

Almost surely, 2^21100004550 is an apocalyptic number.

21100004550 is an abundant number, since it is smaller than the sum of its proper divisors (37042233930).

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

21100004550 is a wasteful number, since it uses less digits than its factorization.

21100004550 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15629654 (or 15629643 counting only the distinct ones).

The product of its (nonzero) digits is 200, while the sum is 18.

Adding to 21100004550 its reverse (5540000112), we get a palindrome (26640004662).

The spelling of 21100004550 in words is "twenty-one billion, one hundred million, four thousand, five hundred fifty".