65521660 has 12 divisors (see below), whose sum is σ = 137595528. Its totient is φ = 26208656.

The previous prime is 65521639. The next prime is 65521667. The reversal of 65521660 is 6612556.

It is a zygodrome in base 2.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (65521667) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 1638022 + ... + 1638061.

It is an arithmetic number, because the mean of its divisors is an integer number (11466294).

Almost surely, 2^65521660 is an apocalyptic number.

It is an amenable number.

65521660 is an abundant number, since it is smaller than the sum of its proper divisors (72073868).

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

65521660 is a wasteful number, since it uses less digits than its factorization.

65521660 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3276092 (or 3276090 counting only the distinct ones).

The product of its (nonzero) digits is 10800, while the sum is 31.

The square root of 65521660 is about 8094.5450767786. The cubic root of 65521660 is about 403.1453274608.

The spelling of 65521660 in words is "sixty-five million, five hundred twenty-one thousand, six hundred sixty".