221628978900 has 1152 divisors, whose sum is σ = 907319705600. Its totient is φ = 45265651200.

The previous prime is 221628978841. The next prime is 221628978913. The reversal of 221628978900 is 9879826122.

221628978900 is a `hidden beast` number, since 2 + 2 + 1 + 628 + 9 + 7 + 8 + 9 + 0 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 383 ways as a sum of consecutive naturals, for example, 478680069 + ... + 478680531.

Almost surely, 2^221628978900 is an apocalyptic number.

221628978900 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 221628978900, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (453659852800).

221628978900 is an abundant number, since it is smaller than the sum of its proper divisors (685690726700).

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

221628978900 is a wasteful number, since it uses less digits than its factorization.

221628978900 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 586 (or 573 counting only the distinct ones).

The product of its (nonzero) digits is 1741824, while the sum is 54.

The spelling of 221628978900 in words is "two hundred twenty-one billion, six hundred twenty-eight million, nine hundred seventy-eight thousand, nine hundred".