561673980 has 192 divisors, whose sum is σ = 2013312000. Its totient is φ = 127339776.

The previous prime is 561673933. The next prime is 561674011. The reversal of 561673980 is 89376165.

It is a happy number.

561673980 is a `hidden beast` number, since 561 + 6 + 7 + 3 + 9 + 80 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 524886 + ... + 525954.

It is an arithmetic number, because the mean of its divisors is an integer number (10486000).

Almost surely, 2^561673980 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 561673980, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1006656000).

561673980 is an abundant number, since it is smaller than the sum of its proper divisors (1451638020).

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

561673980 is a wasteful number, since it uses less digits than its factorization.

561673980 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1233 (or 1225 counting only the distinct ones).

The product of its (nonzero) digits is 272160, while the sum is 45.

The square root of 561673980 is about 23699.6620229066. The cubic root of 561673980 is about 825.0775464298.

It can be divided in two parts, 561 and 673980, that added together give a triangular number (674541 = T₁₁₆₁).

The spelling of 561673980 in words is "five hundred sixty-one million, six hundred seventy-three thousand, nine hundred eighty".