64661563 has 2 divisors, whose sum is σ = 64661564. Its totient is φ = 64661562.

The previous prime is 64661543. The next prime is 64661587. The reversal of 64661563 is 36516646.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 64661563 - 2¹⁷ = 64530491 is a prime.

It is a super-2 number, since 2×64661563² = 8362235459205938, which contains 22 as substring.

It is equal to p_3821797 and since 64661563 and 3821797 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (64661543) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32330781 + 32330782.

It is an arithmetic number, because the mean of its divisors is an integer number (32330782).

Almost surely, 2^64661563 is an apocalyptic number.

64661563 is a deficient number, since it is larger than the sum of its proper divisors (1).

64661563 is an equidigital number, since it uses as much as digits as its factorization.

64661563 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 77760, while the sum is 37.

The square root of 64661563 is about 8041.2413842640. The cubic root of 64661563 is about 401.3735343599.

The spelling of 64661563 in words is "sixty-four million, six hundred sixty-one thousand, five hundred sixty-three".