65605021 has 4 divisors (see below), whose sum is σ = 67721344. Its totient is φ = 63488700.

The previous prime is 65605019. The next prime is 65605037. The reversal of 65605021 is 12050656.

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 65605021 - 2¹ = 65605019 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (65605621) 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, 1058115 + ... + 1058176.

It is an arithmetic number, because the mean of its divisors is an integer number (16930336).

Almost surely, 2^65605021 is an apocalyptic number.

It is an amenable number.

65605021 is a deficient number, since it is larger than the sum of its proper divisors (2116323).

65605021 is a wasteful number, since it uses less digits than its factorization.

65605021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2116322.

The product of its (nonzero) digits is 1800, while the sum is 25.

The square root of 65605021 is about 8099.6926484898. The cubic root of 65605021 is about 403.3162244107.

Adding to 65605021 its reverse (12050656), we get a palindrome (77655677).

The spelling of 65605021 in words is "sixty-five million, six hundred five thousand, twenty-one".