1561121316 has 48 divisors (see below), whose sum is σ = 4156750080. Its totient is φ = 506308320.

The previous prime is 1561121311. The next prime is 1561121351. The reversal of 1561121316 is 6131211651.

1561121316 is a `hidden beast` number, since 15 + 611 + 2 + 1 + 31 + 6 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a self number, because there is not a number n which added to its sum of digits gives 1561121316.

It is not an unprimeable number, because it can be changed into a prime (1561121311) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 191340 + ... + 199331.

It is an arithmetic number, because the mean of its divisors is an integer number (86598960).

Almost surely, 2^1561121316 is an apocalyptic number.

It is an amenable number.

1561121316 is an abundant number, since it is smaller than the sum of its proper divisors (2595628764).

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

1561121316 is a wasteful number, since it uses less digits than its factorization.

1561121316 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 390721 (or 390713 counting only the distinct ones).

The product of its digits is 1080, while the sum is 27.

The square root of 1561121316 is about 39511.0277770650. The cubic root of 1561121316 is about 1160.0558128120.

Adding to 1561121316 its reverse (6131211651), we get a palindrome (7692332967).

The spelling of 1561121316 in words is "one billion, five hundred sixty-one million, one hundred twenty-one thousand, three hundred sixteen".