1561209195 has 128 divisors (see below), whose sum is σ = 3427522560. Its totient is φ = 587243520.

The previous prime is 1561209151. The next prime is 1561209227. The reversal of 1561209195 is 5919021651.

It is not a de Polignac number, because 1561209195 - 2¹⁸ = 1560947051 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 439125 + ... + 442665.

It is an arithmetic number, because the mean of its divisors is an integer number (26777520).

Almost surely, 2^1561209195 is an apocalyptic number.

1561209195 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

1561209195 is an abundant number, since it is smaller than the sum of its proper divisors (1866313365).

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

1561209195 is a wasteful number, since it uses less digits than its factorization.

1561209195 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3605.

The product of its (nonzero) digits is 24300, while the sum is 39.

The square root of 1561209195 is about 39512.1398433443. The cubic root of 1561209195 is about 1160.0775797797.

The spelling of 1561209195 in words is "one billion, five hundred sixty-one million, two hundred nine thousand, one hundred ninety-five".