63661643 has 4 divisors (see below), whose sum is σ = 65214408. Its totient is φ = 62108880.

The previous prime is 63661607. The next prime is 63661667. The reversal of 63661643 is 34616636.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 63661643 - 2⁶ = 63661579 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (63661943) 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, 776321 + ... + 776402.

It is an arithmetic number, because the mean of its divisors is an integer number (16303602).

Almost surely, 2^63661643 is an apocalyptic number.

63661643 is a deficient number, since it is larger than the sum of its proper divisors (1552765).

63661643 is a wasteful number, since it uses less digits than its factorization.

63661643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1552764.

The product of its digits is 46656, while the sum is 35.

The square root of 63661643 is about 7978.8246628185. The cubic root of 63661643 is about 399.2938436750.

The spelling of 63661643 in words is "sixty-three million, six hundred sixty-one thousand, six hundred forty-three".