1561365806 has 64 divisors (see below), whose sum is σ = 3162862080. Its totient is φ = 558264960.

The previous prime is 1561365797. The next prime is 1561365857. The reversal of 1561365806 is 6085631651.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 356180 + ... + 360536.

It is an arithmetic number, because the mean of its divisors is an integer number (49419720).

Almost surely, 2^1561365806 is an apocalyptic number.

1561365806 is an abundant number, since it is smaller than the sum of its proper divisors (1601496274).

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

1561365806 is a wasteful number, since it uses less digits than its factorization.

1561365806 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4569.

The product of its (nonzero) digits is 129600, while the sum is 41.

The square root of 1561365806 is about 39514.1216022829. The cubic root of 1561365806 is about 1160.1163691223.

The spelling of 1561365806 in words is "one billion, five hundred sixty-one million, three hundred sixty-five thousand, eight hundred six".