21207105450 has 96 divisors (see below), whose sum is σ = 58482328320. Its totient is φ = 5650876800.

The previous prime is 21207105427. The next prime is 21207105461. The reversal of 21207105450 is 5450170212.

21207105450 is a `hidden beast` number, since 2 + 1 + 207 + 1 + 0 + 5 + 450 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1994047 + ... + 2004653.

It is an arithmetic number, because the mean of its divisors is an integer number (609190920).

Almost surely, 2^21207105450 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21207105450, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29241164160).

21207105450 is an abundant number, since it is smaller than the sum of its proper divisors (37275222870).

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

21207105450 is a wasteful number, since it uses less digits than its factorization.

21207105450 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12109 (or 12098 counting only the distinct ones).

The product of its (nonzero) digits is 2800, while the sum is 27.

Adding to 21207105450 its reverse (5450170212), we get a palindrome (26657275662).

The spelling of 21207105450 in words is "twenty-one billion, two hundred seven million, one hundred five thousand, four hundred fifty".