561191904 has 576 divisors, whose sum is σ = 2201472000. Its totient is φ = 134120448.

The previous prime is 561191863. The next prime is 561191921. The reversal of 561191904 is 409191165.

561191904 is a `hidden beast` number, since 561 + 1 + 9 + 1 + 90 + 4 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 24399637 + ... + 24399659.

It is an arithmetic number, because the mean of its divisors is an integer number (3822000).

Almost surely, 2^561191904 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 561191904, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1100736000).

561191904 is an abundant number, since it is smaller than the sum of its proper divisors (1640280096).

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

561191904 is a wasteful number, since it uses less digits than its factorization.

561191904 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 92 (or 67 counting only the distinct ones).

The product of its (nonzero) digits is 9720, while the sum is 36.

The square root of 561191904 is about 23689.4893148839. The cubic root of 561191904 is about 824.8414284764.

The spelling of 561191904 in words is "five hundred sixty-one million, one hundred ninety-one thousand, nine hundred four".