21628417500 has 450 divisors, whose sum is σ = 73750092416. Its totient is φ = 5524848000.

The previous prime is 21628417493. The next prime is 21628417519. The reversal of 21628417500 is 571482612.

21628417500 is a `hidden beast` number, since 2 + 1 + 62 + 84 + 17 + 500 = 666.

It is a tau number, because it is divible by the number of its divisors (450).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 149 ways as a sum of consecutive naturals, for example, 170302437 + ... + 170302563.

Almost surely, 2^21628417500 is an apocalyptic number.

21628417500 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21628417500, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36875046208).

21628417500 is an abundant number, since it is smaller than the sum of its proper divisors (52121674916).

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

21628417500 is a wasteful number, since it uses less digits than its factorization.

21628417500 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 221 (or 166 counting only the distinct ones).

The product of its (nonzero) digits is 26880, while the sum is 36.

The spelling of 21628417500 in words is "twenty-one billion, six hundred twenty-eight million, four hundred seventeen thousand, five hundred".