65661406200 has 576 divisors, whose sum is σ = 245826453600. Its totient is φ = 15601766400.

The previous prime is 65661406199. The next prime is 65661406207. The reversal of 65661406200 is 260416656.

It is a happy number.

It is a super-2 number, since 2×65661406200² (a number of 22 digits) contains 22 as substring.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (65661406207) by changing a digit.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 156709591 + ... + 156710009.

Almost surely, 2^65661406200 is an apocalyptic number.

65661406200 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 65661406200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (122913226800).

65661406200 is an abundant number, since it is smaller than the sum of its proper divisors (180165047400).

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

65661406200 is a wasteful number, since it uses less digits than its factorization.

65661406200 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 672 (or 660 counting only the distinct ones).

The product of its (nonzero) digits is 51840, while the sum is 36.

The spelling of 65661406200 in words is "sixty-five billion, six hundred sixty-one million, four hundred six thousand, two hundred".