21110442550 has 24 divisors (see below), whose sum is σ = 39269279016. Its totient is φ = 8443347840.

The previous prime is 21110442541. The next prime is 21110442557. The reversal of 21110442550 is 5524401112.

It is a Harshad number since it is a multiple of its sum of digits (25).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21110442557) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 887614 + ... + 911086.

It is an arithmetic number, because the mean of its divisors is an integer number (1636219959).

Almost surely, 2^21110442550 is an apocalyptic number.

21110442550 is a deficient number, since it is larger than the sum of its proper divisors (18158836466).

21110442550 is a wasteful number, since it uses less digits than its factorization.

21110442550 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41472 (or 41467 counting only the distinct ones).

The product of its (nonzero) digits is 1600, while the sum is 25.

Adding to 21110442550 its reverse (5524401112), we get a palindrome (26634843662).

The spelling of 21110442550 in words is "twenty-one billion, one hundred ten million, four hundred forty-two thousand, five hundred fifty".