216428723550 has 720 divisors, whose sum is σ = 698673563280. Its totient is φ = 49358315520.

The previous prime is 216428723519. The next prime is 216428723629. The reversal of 216428723550 is 55327824612.

216428723550 is a `hidden beast` number, since 2 + 1 + 6 + 4 + 28 + 72 + 3 + 550 = 666.

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

It is a junction number, because it is equal to n+sod(n) for n = 216428723496 and 216428723505.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 359 ways as a sum of consecutive naturals, for example, 1121392254 + ... + 1121392446.

It is an arithmetic number, because the mean of its divisors is an integer number (970379949).

Almost surely, 2^216428723550 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 216428723550, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (349336781640).

216428723550 is an abundant number, since it is smaller than the sum of its proper divisors (482244839730).

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

216428723550 is a wasteful number, since it uses less digits than its factorization.

216428723550 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 327 (or 294 counting only the distinct ones).

The product of its (nonzero) digits is 806400, while the sum is 45.

The spelling of 216428723550 in words is "two hundred sixteen billion, four hundred twenty-eight million, seven hundred twenty-three thousand, five hundred fifty".