1220401728 has 420 divisors, whose sum is σ = 4499457600. Its totient is φ = 320246784.

The previous prime is 1220401727. The next prime is 1220401733. The reversal of 1220401728 is 8271040221.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1220401723) by changing a digit.

It is a polite number, since it can be written in 59 ways as a sum of consecutive naturals, for example, 6132573 + ... + 6132771.

Almost surely, 2^1220401728 is an apocalyptic number.

1220401728 is a gapful number since it is divisible by the number (18) 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 1220401728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2249728800).

1220401728 is an abundant number, since it is smaller than the sum of its proper divisors (3279055872).

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

1220401728 is a wasteful number, since it uses less digits than its factorization.

1220401728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 256 (or 224 counting only the distinct ones).

The product of its (nonzero) digits is 1792, while the sum is 27.

The square root of 1220401728 is about 34934.2486394083. The cubic root of 1220401728 is about 1068.6470009696.

Adding to 1220401728 its reverse (8271040221), we get a palindrome (9491441949).

The spelling of 1220401728 in words is "one billion, two hundred twenty million, four hundred one thousand, seven hundred twenty-eight".