66561510740 has 48 divisors (see below), whose sum is σ = 140533060752. Its totient is φ = 26481386496.

The previous prime is 66561510737. The next prime is 66561510817. The reversal of 66561510740 is 4701516566.

It can be written as a sum of positive squares in 8 ways, for example, as 721029904 + 65840480836 = 26852^2 + 256594^2 .

It is a super-2 number, since 2×66561510740² (a number of 22 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2885894 + ... + 2908866.

It is an arithmetic number, because the mean of its divisors is an integer number (2927772099).

Almost surely, 2^66561510740 is an apocalyptic number.

It is an amenable number.

66561510740 is an abundant number, since it is smaller than the sum of its proper divisors (73971550012).

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

66561510740 is a wasteful number, since it uses less digits than its factorization.

66561510740 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23756 (or 23754 counting only the distinct ones).

The product of its (nonzero) digits is 151200, while the sum is 41.

The spelling of 66561510740 in words is "sixty-six billion, five hundred sixty-one million, five hundred ten thousand, seven hundred forty".