63991671 has 16 divisors (see below), whose sum is σ = 86531328. Its totient is φ = 42060800.

The previous prime is 63991651. The next prime is 63991673. The reversal of 63991671 is 17619936.

It is a cyclic number.

It is not a de Polignac number, because 63991671 - 2¹⁴ = 63975287 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (63991673) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 99511 + ... + 100151.

It is an arithmetic number, because the mean of its divisors is an integer number (5408208).

Almost surely, 2^63991671 is an apocalyptic number.

63991671 is a deficient number, since it is larger than the sum of its proper divisors (22539657).

63991671 is a wasteful number, since it uses less digits than its factorization.

63991671 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1062.

The product of its digits is 61236, while the sum is 42.

The square root of 63991671 is about 7999.4794205623. The cubic root of 63991671 is about 399.9826471639.

The spelling of 63991671 in words is "sixty-three million, nine hundred ninety-one thousand, six hundred seventy-one".