65561633280 has 1440 divisors, whose sum is σ = 282889518912. Its totient is φ = 14452162560.

The previous prime is 65561633261. The next prime is 65561633303. The reversal of 65561633280 is 8233616556.

65561633280 is a `hidden beast` number, since 6 + 5 + 5 + 6 + 1 + 633 + 2 + 8 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (1440).

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 143 ways as a sum of consecutive naturals, for example, 978531807 + ... + 978531873.

Almost surely, 2^65561633280 is an apocalyptic number.

65561633280 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 65561633280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (141444759456).

65561633280 is an abundant number, since it is smaller than the sum of its proper divisors (217327885632).

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

65561633280 is a wasteful number, since it uses less digits than its factorization.

65561633280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 140 (or 101 counting only the distinct ones).

The product of its (nonzero) digits is 777600, while the sum is 45.

The spelling of 65561633280 in words is "sixty-five billion, five hundred sixty-one million, six hundred thirty-three thousand, two hundred eighty".