1240405812 has 30 divisors (see below), whose sum is σ = 3242666658. Its totient is φ = 413468496.

The previous prime is 1240405787. The next prime is 1240405813. The reversal of 1240405812 is 2185040421.

1240405812 is a `hidden beast` number, since 1 + 2 + 40 + 40 + 581 + 2 = 666.

It can be written as a sum of positive squares in only one way, i.e., 775399716 + 465006096 = 27846^2 + 21564^2 .

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1240405813) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 1913883 + ... + 1914530.

Almost surely, 2^1240405812 is an apocalyptic number.

1240405812 is a gapful number since it is divisible by the number (12) formed by its first and last digit.

It is an amenable number.

1240405812 is an abundant number, since it is smaller than the sum of its proper divisors (2002260846).

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

1240405812 is a wasteful number, since it uses less digits than its factorization.

1240405812 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3828429 (or 3828418 counting only the distinct ones).

The product of its (nonzero) digits is 2560, while the sum is 27.

The square root of 1240405812 is about 35219.3953951512. The cubic root of 1240405812 is about 1074.4542568286.

The spelling of 1240405812 in words is "one billion, two hundred forty million, four hundred five thousand, eight hundred twelve".