64611221 has 4 divisors (see below), whose sum is σ = 64685772. Its totient is φ = 64536672.

The previous prime is 64611199. The next prime is 64611227. The reversal of 64611221 is 12211646.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12211646 = 2 ⋅6105823.

It can be written as a sum of positive squares in 2 ways, for example, as 56460196 + 8151025 = 7514^2 + 2855^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-64611221 is a prime.

It is a super-2 number, since 2×64611221² = 8349219758221682, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64611227) 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, 35960 + ... + 37713.

It is an arithmetic number, because the mean of its divisors is an integer number (16171443).

Almost surely, 2^64611221 is an apocalyptic number.

It is an amenable number.

64611221 is a deficient number, since it is larger than the sum of its proper divisors (74551).

64611221 is an equidigital number, since it uses as much as digits as its factorization.

64611221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 74550.

The product of its digits is 576, while the sum is 23.

The square root of 64611221 is about 8038.1105366871. The cubic root of 64611221 is about 401.2693447323.

Adding to 64611221 its reverse (12211646), we get a palindrome (76822867).

The spelling of 64611221 in words is "sixty-four million, six hundred eleven thousand, two hundred twenty-one".