64646221 has 2 divisors, whose sum is σ = 64646222. Its totient is φ = 64646220.

The previous prime is 64646209. The next prime is 64646233. The reversal of 64646221 is 12264646.

It is a balanced prime because it is at equal distance from previous prime (64646209) and next prime (64646233).

It can be written as a sum of positive squares in only one way, i.e., 54597321 + 10048900 = 7389^2 + 3170^2 .

It is a cyclic number.

It is not a de Polignac number, because 64646221 - 2⁷ = 64646093 is a prime.

It is equal to p_3820927 and since 64646221 and 3820927 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (64646251) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32323110 + 32323111.

It is an arithmetic number, because the mean of its divisors is an integer number (32323111).

Almost surely, 2^64646221 is an apocalyptic number.

It is an amenable number.

64646221 is a deficient number, since it is larger than the sum of its proper divisors (1).

64646221 is an equidigital number, since it uses as much as digits as its factorization.

64646221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 13824, while the sum is 31.

The square root of 64646221 is about 8040.2873704862. The cubic root of 64646221 is about 401.3417877314.

The spelling of 64646221 in words is "sixty-four million, six hundred forty-six thousand, two hundred twenty-one".