21455450153550 has 432 divisors, whose sum is σ = 73024354570752. Its totient is φ = 4414942540800.

The previous prime is 21455450153513. The next prime is 21455450153611. The reversal of 21455450153550 is 5535105455412.

21455450153550 is a `hidden beast` number, since 2 + 1 + 4 + 5 + 5 + 45 + 0 + 1 + 53 + 550 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21455450153496 and 21455450153505.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 215 ways as a sum of consecutive naturals, for example, 20425695 + ... + 21450405.

Almost surely, 2^{21455450153550} is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21455450153550, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36512177285376).

21455450153550 is an abundant number, since it is smaller than the sum of its proper divisors (51568904417202).

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

21455450153550 is a wasteful number, since it uses less digits than its factorization.

21455450153550 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1024793 (or 1024768 counting only the distinct ones).

The product of its (nonzero) digits is 1500000, while the sum is 45.

The spelling of 21455450153550 in words is "twenty-one trillion, four hundred fifty-five billion, four hundred fifty million, one hundred fifty-three thousand, five hundred fifty".