1561251155 has 16 divisors (see below), whose sum is σ = 1956412224. Its totient is φ = 1193808000.

The previous prime is 1561251143. The next prime is 1561251161. The reversal of 1561251155 is 5511521651.

It is not a de Polignac number, because 1561251155 - 2¹⁴ = 1561234771 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 179405 + ... + 187905.

It is an arithmetic number, because the mean of its divisors is an integer number (122275764).

Almost surely, 2^1561251155 is an apocalyptic number.

1561251155 is a deficient number, since it is larger than the sum of its proper divisors (395161069).

1561251155 is a wasteful number, since it uses less digits than its factorization.

1561251155 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10126.

The product of its digits is 7500, while the sum is 32.

The square root of 1561251155 is about 39512.6708158282. The cubic root of 1561251155 is about 1160.0879726682.

The spelling of 1561251155 in words is "one billion, five hundred sixty-one million, two hundred fifty-one thousand, one hundred fifty-five".