1561787061 has 16 divisors (see below), whose sum is σ = 2193408000. Its totient is φ = 985750128.

The previous prime is 1561787027. The next prime is 1561787063. The reversal of 1561787061 is 1607871651.

It is a happy number.

It is not a de Polignac number, because 1561787061 - 2⁶ = 1561786997 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1561787063) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 88780 + ... + 104906.

It is an arithmetic number, because the mean of its divisors is an integer number (137088000).

Almost surely, 2^1561787061 is an apocalyptic number.

It is an amenable number.

1561787061 is a deficient number, since it is larger than the sum of its proper divisors (631620939).

1561787061 is a wasteful number, since it uses less digits than its factorization.

1561787061 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17848.

The product of its (nonzero) digits is 70560, while the sum is 42.

The square root of 1561787061 is about 39519.4516788885. The cubic root of 1561787061 is about 1160.2206925028.

The spelling of 1561787061 in words is "one billion, five hundred sixty-one million, seven hundred eighty-seven thousand, sixty-one".