561163691 has 16 divisors (see below), whose sum is σ = 635834880. Its totient is φ = 490805280.

The previous prime is 561163663. The next prime is 561163699. The reversal of 561163691 is 196361165.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 561163691 - 2⁶ = 561163627 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (561163699) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 21305 + ... + 39701.

It is an arithmetic number, because the mean of its divisors is an integer number (39739680).

Almost surely, 2^561163691 is an apocalyptic number.

561163691 is a deficient number, since it is larger than the sum of its proper divisors (74671189).

561163691 is a wasteful number, since it uses less digits than its factorization.

561163691 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18514.

The product of its digits is 29160, while the sum is 38.

The square root of 561163691 is about 23688.8938323426. The cubic root of 561163691 is about 824.8276057294.

The spelling of 561163691 in words is "five hundred sixty-one million, one hundred sixty-three thousand, six hundred ninety-one".