1213509780 has 72 divisors (see below), whose sum is σ = 4206838272. Its totient is φ = 277373376.

The previous prime is 1213509767. The next prime is 1213509797. The reversal of 1213509780 is 879053121.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

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 23 ways as a sum of consecutive naturals, for example, 480292 + ... + 482811.

Almost surely, 2^1213509780 is an apocalyptic number.

1213509780 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1213509780 is an abundant number, since it is smaller than the sum of its proper divisors (2993328492).

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

1213509780 is a wasteful number, since it uses less digits than its factorization.

1213509780 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 963125 (or 963120 counting only the distinct ones).

The product of its (nonzero) digits is 15120, while the sum is 36.

The square root of 1213509780 is about 34835.4672711591. The cubic root of 1213509780 is about 1066.6315533146.

The spelling of 1213509780 in words is "one billion, two hundred thirteen million, five hundred nine thousand, seven hundred eighty".