1561323256 has 8 divisors (see below), whose sum is σ = 2927481120. Its totient is φ = 780661624.

The previous prime is 1561323251. The next prime is 1561323289. The reversal of 1561323256 is 6523231651.

It is a tau number, because it is divible by the number of its divisors (8).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1561323251) 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 as a sum of consecutive naturals, namely, 97582696 + ... + 97582711.

It is an arithmetic number, because the mean of its divisors is an integer number (365935140).

Almost surely, 2^1561323256 is an apocalyptic number.

It is an amenable number.

1561323256 is a deficient number, since it is larger than the sum of its proper divisors (1366157864).

1561323256 is a wasteful number, since it uses less digits than its factorization.

1561323256 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 195165413 (or 195165409 counting only the distinct ones).

The product of its digits is 32400, while the sum is 34.

The square root of 1561323256 is about 39513.5831835079. The cubic root of 1561323256 is about 1160.1058306140.

The spelling of 1561323256 in words is "one billion, five hundred sixty-one million, three hundred twenty-three thousand, two hundred fifty-six".