1561963977378 has 48 divisors (see below), whose sum is σ = 3871984908480. Its totient is φ = 445783354848.

The previous prime is 1561963977377. The next prime is 1561963977401. The reversal of 1561963977378 is 8737793691651.

It is a happy number.

1561963977378 is a `hidden beast` number, since 15 + 6 + 1 + 96 + 397 + 73 + 78 = 666.

It is not an unprimeable number, because it can be changed into a prime (1561963977377) 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, 6719533 + ... + 6948096.

It is an arithmetic number, because the mean of its divisors is an integer number (80666352260).

Almost surely, 2^{1561963977378} is an apocalyptic number.

1561963977378 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

1561963977378 is an abundant number, since it is smaller than the sum of its proper divisors (2310020931102).

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

1561963977378 is a wasteful number, since it uses less digits than its factorization.

1561963977378 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13668551 (or 13668548 counting only the distinct ones).

The product of its digits is 360067680, while the sum is 72.

The spelling of 1561963977378 in words is "one trillion, five hundred sixty-one billion, nine hundred sixty-three million, nine hundred seventy-seven thousand, three hundred seventy-eight".