1561630906 has 16 divisors (see below), whose sum is σ = 2556002880. Its totient is φ = 709663680.

The previous prime is 1561630853. The next prime is 1561630909. The reversal of 1561630906 is 6090361651.

It is not an unprimeable number, because it can be changed into a prime (1561630909) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 176275 + ... + 184921.

It is an arithmetic number, because the mean of its divisors is an integer number (159750180).

Almost surely, 2^1561630906 is an apocalyptic number.

1561630906 is a deficient number, since it is larger than the sum of its proper divisors (994371974).

1561630906 is a wasteful number, since it uses less digits than its factorization.

1561630906 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16869.

The product of its (nonzero) digits is 29160, while the sum is 37.

The square root of 1561630906 is about 39517.4759568472. The cubic root of 1561630906 is about 1160.1820230611.

The spelling of 1561630906 in words is "one billion, five hundred sixty-one million, six hundred thirty thousand, nine hundred six".