65661601 has 4 divisors (see below), whose sum is σ = 65802672. Its totient is φ = 65520532.

The previous prime is 65661517. The next prime is 65661611. The reversal of 65661601 is 10616656.

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 not a de Polignac number, because 65661601 - 2¹⁵ = 65628833 is a prime.

It is a super-2 number, since 2×65661601² = 8622891691766402, which contains 22 as substring.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (65661611) 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, 69835 + ... + 70768.

It is an arithmetic number, because the mean of its divisors is an integer number (16450668).

Almost surely, 2^65661601 is an apocalyptic number.

It is an amenable number.

65661601 is a deficient number, since it is larger than the sum of its proper divisors (141071).

65661601 is a wasteful number, since it uses less digits than its factorization.

65661601 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 141070.

The product of its (nonzero) digits is 6480, while the sum is 31.

The square root of 65661601 is about 8103.1846208759. The cubic root of 65661601 is about 403.4321356353.

The spelling of 65661601 in words is "sixty-five million, six hundred sixty-one thousand, six hundred one".