1219400720 has 40 divisors (see below), whose sum is σ = 2838073560. Its totient is φ = 487249920.

The previous prime is 1219400719. The next prime is 1219400723. The reversal of 1219400720 is 270049121.

It can be written as a sum of positive squares in 4 ways, for example, as 351037696 + 868363024 = 18736^2 + 29468^2 .

It is a tau number, because it is divible by the number of its divisors (40).

It is a self number, because there is not a number n which added to its sum of digits gives 1219400720.

It is not an unprimeable number, because it can be changed into a prime (1219400723) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 74216 + ... + 89144.

It is an arithmetic number, because the mean of its divisors is an integer number (70951839).

Almost surely, 2^1219400720 is an apocalyptic number.

1219400720 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1219400720 is an abundant number, since it is smaller than the sum of its proper divisors (1618672840).

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

1219400720 is a wasteful number, since it uses less digits than its factorization.

1219400720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15963 (or 15957 counting only the distinct ones).

The product of its (nonzero) digits is 1008, while the sum is 26.

The square root of 1219400720 is about 34919.9186711539. The cubic root of 1219400720 is about 1068.3547428881.

Adding to 1219400720 its reverse (270049121), we get a palindrome (1489449841).

The spelling of 1219400720 in words is "one billion, two hundred nineteen million, four hundred thousand, seven hundred twenty".