21450550 has 48 divisors (see below), whose sum is σ = 44586432. Its totient is φ = 7610400.

The previous prime is 21450523. The next prime is 21450553. The reversal of 21450550 is 5505412.

It is a Harshad number since it is a multiple of its sum of digits (22).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21450553) 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, 23197 + ... + 24103.

It is an arithmetic number, because the mean of its divisors is an integer number (928884).

Almost surely, 2^21450550 is an apocalyptic number.

21450550 is an abundant number, since it is smaller than the sum of its proper divisors (23135882).

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

21450550 is a wasteful number, since it uses less digits than its factorization.

21450550 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 973 (or 968 counting only the distinct ones).

The product of its (nonzero) digits is 1000, while the sum is 22.

The square root of 21450550 is about 4631.4738474917. The cubic root of 21450550 is about 277.8515415955.

Adding to 21450550 its reverse (5505412), we get a palindrome (26955962).

The spelling of 21450550 in words is "twenty-one million, four hundred fifty thousand, five hundred fifty".