1561944384 has 840 divisors, whose sum is σ = 6474793248. Its totient is φ = 365783040.

The previous prime is 1561944359. The next prime is 1561944443. The reversal of 1561944384 is 4834491651.

1561944384 is a `hidden beast` number, since 1 + 561 + 9 + 4 + 4 + 3 + 84 = 666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 119 ways as a sum of consecutive naturals, for example, 36324267 + ... + 36324309.

Almost surely, 2^1561944384 is an apocalyptic number.

1561944384 is a gapful number since it is divisible by the number (14) 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 1561944384, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3237396624).

1561944384 is an abundant number, since it is smaller than the sum of its proper divisors (4912848864).

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

1561944384 is a wasteful number, since it uses less digits than its factorization.

1561944384 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 105 (or 79 counting only the distinct ones).

The product of its digits is 414720, while the sum is 45.

The square root of 1561944384 is about 39521.4420789525. The cubic root of 1561944384 is about 1160.2596485756.

The spelling of 1561944384 in words is "one billion, five hundred sixty-one million, nine hundred forty-four thousand, three hundred eighty-four".