1228400640 has 240 divisors, whose sum is σ = 4405941540. Its totient is φ = 327352320.

The previous prime is 1228400627. The next prime is 1228400659. The reversal of 1228400640 is 460048221.

1228400640 is a `hidden beast` number, since 12 + 2 + 8 + 4 + 0 + 0 + 640 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 1214383104 + 14017536 = 34848^2 + 3744^2 .

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 (27).

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 828700 + ... + 830180.

Almost surely, 2^1228400640 is an apocalyptic number.

1228400640 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 1228400640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2202970770).

1228400640 is an abundant number, since it is smaller than the sum of its proper divisors (3177540900).

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

1228400640 is an equidigital number, since it uses as much as digits as its factorization.

1228400640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1520 (or 1491 counting only the distinct ones).

The product of its (nonzero) digits is 3072, while the sum is 27.

The square root of 1228400640 is about 35048.5469028318. The cubic root of 1228400640 is about 1070.9766725141.

Adding to 1228400640 its reverse (460048221), we get a palindrome (1688448861).

The spelling of 1228400640 in words is "one billion, two hundred twenty-eight million, four hundred thousand, six hundred forty".