65660261 has 4 divisors (see below), whose sum is σ = 66004224. Its totient is φ = 65316300.

The previous prime is 65660251. The next prime is 65660281. The reversal of 65660261 is 16206656.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-65660261 is a prime.

It is a super-2 number, since 2×65660261² = 8622539749176242, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (65660251) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 171695 + ... + 172076.

It is an arithmetic number, because the mean of its divisors is an integer number (16501056).

Almost surely, 2^65660261 is an apocalyptic number.

It is an amenable number.

65660261 is a deficient number, since it is larger than the sum of its proper divisors (343963).

65660261 is a wasteful number, since it uses less digits than its factorization.

65660261 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 343962.

The product of its (nonzero) digits is 12960, while the sum is 32.

The square root of 65660261 is about 8103.1019369128. The cubic root of 65660261 is about 403.4293912473.

The spelling of 65660261 in words is "sixty-five million, six hundred sixty thousand, two hundred sixty-one".