209230777728 has 384 divisors, whose sum is σ = 749587392000. Its totient is φ = 57180017664.

The previous prime is 209230777697. The next prime is 209230777729. The reversal of 209230777728 is 827777032902.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (384).

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (209230777729) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 3868053 + ... + 3921771.

It is an arithmetic number, because the mean of its divisors is an integer number (1952050500).

Almost surely, 2^209230777728 is an apocalyptic number.

209230777728 is a gapful number since it is divisible by the number (28) 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 209230777728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (374793696000).

209230777728 is an abundant number, since it is smaller than the sum of its proper divisors (540356614272).

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

209230777728 is a wasteful number, since it uses less digits than its factorization.

209230777728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53779 (or 53754 counting only the distinct ones).

The product of its (nonzero) digits is 4148928, while the sum is 54.

The spelling of 209230777728 in words is "two hundred nine billion, two hundred thirty million, seven hundred seventy-seven thousand, seven hundred twenty-eight".