1215780078 has 16 divisors (see below), whose sum is σ = 2472773760. Its totient is φ = 398391096.

The previous prime is 1215780061. The next prime is 1215780121. The reversal of 1215780078 is 8700875121.

It is a congruent number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 1716850 + ... + 1717557.

It is an arithmetic number, because the mean of its divisors is an integer number (154548360).

Almost surely, 2^1215780078 is an apocalyptic number.

1215780078 is an abundant number, since it is smaller than the sum of its proper divisors (1256993682).

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

1215780078 is a wasteful number, since it uses less digits than its factorization.

1215780078 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3434471.

The product of its (nonzero) digits is 31360, while the sum is 39.

The square root of 1215780078 is about 34868.0380577973. The cubic root of 1215780078 is about 1067.2963090931.

It can be divided in two parts, 12157 and 80078, that added together give a triangular number (92235 = T₄₂₉).

The spelling of 1215780078 in words is "one billion, two hundred fifteen million, seven hundred eighty thousand, seventy-eight".