1213646440 has 16 divisors (see below), whose sum is σ = 2730704580. Its totient is φ = 485458560.

The previous prime is 1213646407. The next prime is 1213646471. The reversal of 1213646440 is 446463121.

It can be written as a sum of positive squares in 2 ways, for example, as 1209509284 + 4137156 = 34778^2 + 2034^2 .

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 3 ways as a sum of consecutive naturals, for example, 15170541 + ... + 15170620.

Almost surely, 2^1213646440 is an apocalyptic number.

1213646440 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1213646440 is an abundant number, since it is smaller than the sum of its proper divisors (1517058140).

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

1213646440 is a wasteful number, since it uses less digits than its factorization.

1213646440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30341172 (or 30341168 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 31.

The square root of 1213646440 is about 34837.4287225679. The cubic root of 1213646440 is about 1066.6715915571.

The spelling of 1213646440 in words is "one billion, two hundred thirteen million, six hundred forty-six thousand, four hundred forty".