65560021 has 4 divisors (see below), whose sum is σ = 65870944. Its totient is φ = 65249100.

The previous prime is 65559997. The next prime is 65560031. The reversal of 65560021 is 12006556.

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 65560021 - 2⁹ = 65559509 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 (65560031) 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, 155145 + ... + 155566.

It is an arithmetic number, because the mean of its divisors is an integer number (16467736).

Almost surely, 2^65560021 is an apocalyptic number.

It is an amenable number.

65560021 is a deficient number, since it is larger than the sum of its proper divisors (310923).

65560021 is a wasteful number, since it uses less digits than its factorization.

65560021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 310922.

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

The square root of 65560021 is about 8096.9142887893. The cubic root of 65560021 is about 403.2239886790.

Adding to 65560021 its reverse (12006556), we get a palindrome (77566577).

The spelling of 65560021 in words is "sixty-five million, five hundred sixty thousand, twenty-one".