1561978080 has 480 divisors, whose sum is σ = 6065224704. Its totient is φ = 376233984.

The previous prime is 1561978069. The next prime is 1561978081. The reversal of 1561978080 is 808791651.

1561978080 is a `hidden beast` number, since 1 + 561 + 9 + 7 + 8 + 0 + 80 = 666.

It is a tau number, because it is divible by the number of its divisors (480).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1561978081) by changing a digit.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 12298977 + ... + 12299103.

Almost surely, 2^1561978080 is an apocalyptic number.

1561978080 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1561978080, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3032612352).

1561978080 is an abundant number, since it is smaller than the sum of its proper divisors (4503246624).

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

1561978080 is a wasteful number, since it uses less digits than its factorization.

1561978080 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 240 (or 223 counting only the distinct ones).

The product of its (nonzero) digits is 120960, while the sum is 45.

The square root of 1561978080 is about 39521.8683768872. The cubic root of 1561978080 is about 1160.2679919858.

The spelling of 1561978080 in words is "one billion, five hundred sixty-one million, nine hundred seventy-eight thousand, eighty".