1561767378 has 16 divisors (see below), whose sum is σ = 3124704000. Its totient is φ = 520394256.

The previous prime is 1561767359. The next prime is 1561767397. The reversal of 1561767378 is 8737671651.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (1561767359) and next prime (1561767397).

It is a self number, because there is not a number n which added to its sum of digits gives 1561767378.

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, 30850 + ... + 63837.

It is an arithmetic number, because the mean of its divisors is an integer number (195294000).

Almost surely, 2^1561767378 is an apocalyptic number.

1561767378 is an abundant number, since it is smaller than the sum of its proper divisors (1562936622).

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

1561767378 is a wasteful number, since it uses less digits than its factorization.

1561767378 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 97441.

The product of its digits is 1481760, while the sum is 51.

The square root of 1561767378 is about 39519.2026488390. The cubic root of 1561767378 is about 1160.2158184453.

The spelling of 1561767378 in words is "one billion, five hundred sixty-one million, seven hundred sixty-seven thousand, three hundred seventy-eight".