1561378215 has 8 divisors (see below), whose sum is σ = 2498205168. Its totient is φ = 832735040.

The previous prime is 1561378213. The next prime is 1561378223. The reversal of 1561378215 is 5128731651.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1561378215 - 2¹ = 1561378213 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1561378213) 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 7 ways as a sum of consecutive naturals, for example, 52045926 + ... + 52045955.

It is an arithmetic number, because the mean of its divisors is an integer number (312275646).

Almost surely, 2^1561378215 is an apocalyptic number.

1561378215 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

1561378215 is a deficient number, since it is larger than the sum of its proper divisors (936826953).

1561378215 is a wasteful number, since it uses less digits than its factorization.

1561378215 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 104091889.

The product of its digits is 50400, while the sum is 39.

The square root of 1561378215 is about 39514.2786217843. The cubic root of 1561378215 is about 1160.1194424670.

The spelling of 1561378215 in words is "one billion, five hundred sixty-one million, three hundred seventy-eight thousand, two hundred fifteen".