21023354550 has 48 divisors (see below), whose sum is σ = 56877734592. Its totient is φ = 5096570400.

The previous prime is 21023354533. The next prime is 21023354581. The reversal of 21023354550 is 5545332012.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 6369064 + ... + 6372363.

It is an arithmetic number, because the mean of its divisors is an integer number (1184952804).

Almost surely, 2^21023354550 is an apocalyptic number.

21023354550 is an abundant number, since it is smaller than the sum of its proper divisors (35854380042).

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

21023354550 is a wasteful number, since it uses less digits than its factorization.

21023354550 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12741453 (or 12741448 counting only the distinct ones).

The product of its (nonzero) digits is 18000, while the sum is 30.

Adding to 21023354550 its reverse (5545332012), we get a palindrome (26568686562).

It can be divided in two parts, 21023 and 354550, that added together give a palindrome (375573).

The spelling of 21023354550 in words is "twenty-one billion, twenty-three million, three hundred fifty-four thousand, five hundred fifty".