1561455378 has 48 divisors (see below), whose sum is σ = 4069965120. Its totient is φ = 422648928.

The previous prime is 1561455377. The next prime is 1561455407. The reversal of 1561455378 is 8735541651.

1561455378 is a `hidden beast` number, since 1 + 561 + 4 + 55 + 37 + 8 = 666.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1561455373) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 323725 + ... + 328512.

It is an arithmetic number, because the mean of its divisors is an integer number (84790940).

Almost surely, 2^1561455378 is an apocalyptic number.

1561455378 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

1561455378 is an abundant number, since it is smaller than the sum of its proper divisors (2508509742).

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

1561455378 is a wasteful number, since it uses less digits than its factorization.

1561455378 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 652271 (or 652268 counting only the distinct ones).

The product of its digits is 504000, while the sum is 45.

The square root of 1561455378 is about 39515.2550036059. The cubic root of 1561455378 is about 1160.1385531094.

The spelling of 1561455378 in words is "one billion, five hundred sixty-one million, four hundred fifty-five thousand, three hundred seventy-eight".