66661641 has 24 divisors (see below), whose sum is σ = 102435840. Its totient is φ = 41629056.

The previous prime is 66661631. The next prime is 66661657. The reversal of 66661641 is 14616666.

It is not a de Polignac number, because 66661641 - 2¹³ = 66653449 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 66661596 and 66661605.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66661631) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 35656 + ... + 37478.

It is an arithmetic number, because the mean of its divisors is an integer number (4268160).

Almost surely, 2^66661641 is an apocalyptic number.

It is an amenable number.

66661641 is a deficient number, since it is larger than the sum of its proper divisors (35774199).

66661641 is a wasteful number, since it uses less digits than its factorization.

66661641 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2085 (or 2082 counting only the distinct ones).

The product of its digits is 31104, while the sum is 36.

The square root of 66661641 is about 8164.6580455032. The cubic root of 66661641 is about 405.4699437422.

The spelling of 66661641 in words is "sixty-six million, six hundred sixty-one thousand, six hundred forty-one".