1220420400 has 240 divisors, whose sum is σ = 4118307840. Its totient is φ = 308505600.

The previous prime is 1220420387. The next prime is 1220420419. The reversal of 1220420400 is 40240221.

It is a tau number, because it is divible by the number of its divisors (240).

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 1220420400.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1971291 + ... + 1971909.

It is an arithmetic number, because the mean of its divisors is an integer number (17159616).

Almost surely, 2^1220420400 is an apocalyptic number.

1220420400 is a gapful number since it is divisible by the number (10) 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 1220420400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2059153920).

1220420400 is an abundant number, since it is smaller than the sum of its proper divisors (2897887440).

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

1220420400 is a wasteful number, since it uses less digits than its factorization.

1220420400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 724 (or 713 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 15.

The square root of 1220420400 is about 34934.5158832923. The cubic root of 1220420400 is about 1068.6524509988.

Adding to 1220420400 its reverse (40240221), we get a palindrome (1260660621).

The spelling of 1220420400 in words is "one billion, two hundred twenty million, four hundred twenty thousand, four hundred".