1561157120 has 80 divisors (see below), whose sum is σ = 3760875360. Its totient is φ = 621502464.

The previous prime is 1561157083. The next prime is 1561157149. The reversal of 1561157120 is 217511651.

1561157120 is digitally balanced in base 6, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (80).

It is a congruent number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 584909 + ... + 587571.

It is an arithmetic number, because the mean of its divisors is an integer number (47010942).

Almost surely, 2^1561157120 is an apocalyptic number.

1561157120 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 1561157120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1880437680).

1561157120 is an abundant number, since it is smaller than the sum of its proper divisors (2199718240).

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

1561157120 is an equidigital number, since it uses as much as digits as its factorization.

1561157120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2915 (or 2899 counting only the distinct ones).

The product of its (nonzero) digits is 2100, while the sum is 29.

The square root of 1561157120 is about 39511.4808631618. The cubic root of 1561157120 is about 1160.0646812923.

Adding to 1561157120 its reverse (217511651), we get a palindrome (1778668771).

The spelling of 1561157120 in words is "one billion, five hundred sixty-one million, one hundred fifty-seven thousand, one hundred twenty".