1213623440 has 40 divisors (see below), whose sum is σ = 2847581880. Its totient is φ = 480992256.

The previous prime is 1213623413. The next prime is 1213623449. The reversal of 1213623440 is 443263121.

It can be written as a sum of positive squares in 4 ways, for example, as 7311616 + 1206311824 = 2704^2 + 34732^2 .

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

It is not an unprimeable number, because it can be changed into a prime (1213623449) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 60869 + ... + 78308.

It is an arithmetic number, because the mean of its divisors is an integer number (71189547).

Almost surely, 2^1213623440 is an apocalyptic number.

1213623440 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1213623440 is an abundant number, since it is smaller than the sum of its proper divisors (1633958440).

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

1213623440 is a wasteful number, since it uses less digits than its factorization.

1213623440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 139299 (or 139293 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 26.

The square root of 1213623440 is about 34837.0986162740. The cubic root of 1213623440 is about 1066.6648532955.

Adding to 1213623440 its reverse (443263121), we get a palindrome (1656886561).

The spelling of 1213623440 in words is "one billion, two hundred thirteen million, six hundred twenty-three thousand, four hundred forty".