66461211540 has 36 divisors (see below), whose sum is σ = 201599008884. Its totient is φ = 17722989696.

The previous prime is 66461211521. The next prime is 66461211547. The reversal of 66461211540 is 4511216466.

66461211540 is a `hidden beast` number, since 6 + 646 + 1 + 2 + 1 + 1 + 5 + 4 + 0 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 44173110276 + 22288101264 = 210174^2 + 149292^2 .

It is a tau number, because it is divible by the number of its divisors (36).

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

It is a junction number, because it is equal to n+sod(n) for n = 66461211495 and 66461211504.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66461211547) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 184614297 + ... + 184614656.

It is an arithmetic number, because the mean of its divisors is an integer number (5599972469).

Almost surely, 2^66461211540 is an apocalyptic number.

66461211540 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

66461211540 is an abundant number, since it is smaller than the sum of its proper divisors (135137797344).

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

66461211540 is a wasteful number, since it uses less digits than its factorization.

66461211540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 369228968 (or 369228963 counting only the distinct ones).

The product of its (nonzero) digits is 34560, while the sum is 36.

The spelling of 66461211540 in words is "sixty-six billion, four hundred sixty-one million, two hundred eleven thousand, five hundred forty".