21621455055450 has 72 divisors (see below), whose sum is σ = 58102105789728. Its totient is φ = 5764484305440.

The previous prime is 21621455055413. The next prime is 21621455055481. The reversal of 21621455055450 is 5455055412612.

It is a happy number.

21621455055450 is a `hidden beast` number, since 2 + 1 + 6 + 2 + 1 + 4 + 550 + 55 + 45 + 0 = 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 = 21621455055396 and 21621455055405.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 3053664 + ... + 7250363.

It is an arithmetic number, because the mean of its divisors is an integer number (806973691524).

Almost surely, 2^{21621455055450} is an apocalyptic number.

21621455055450 is an abundant number, since it is smaller than the sum of its proper divisors (36480650734278).

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

21621455055450 is a wasteful number, since it uses less digits than its factorization.

21621455055450 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10308708 (or 10308700 counting only the distinct ones).

The product of its (nonzero) digits is 1200000, while the sum is 45.

The spelling of 21621455055450 in words is "twenty-one trillion, six hundred twenty-one billion, four hundred fifty-five million, fifty-five thousand, four hundred fifty".