65661556 has 6 divisors (see below), whose sum is σ = 114907730. Its totient is φ = 32830776.

The previous prime is 65661517. The next prime is 65661611. The reversal of 65661556 is 65516656.

It can be written as a sum of positive squares in only one way, i.e., 37210000 + 28451556 = 6100^2 + 5334^2 .

It is a super-2 number, since 2×65661556² = 8622879872682272, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8207691 + ... + 8207698.

Almost surely, 2^65661556 is an apocalyptic number.

It is an amenable number.

65661556 is a deficient number, since it is larger than the sum of its proper divisors (49246174).

65661556 is a wasteful number, since it uses less digits than its factorization.

65661556 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16415393 (or 16415391 counting only the distinct ones).

The product of its digits is 162000, while the sum is 40.

The square root of 65661556 is about 8103.1818441894. The cubic root of 65661556 is about 403.4320434736.

The spelling of 65661556 in words is "sixty-five million, six hundred sixty-one thousand, five hundred fifty-six".