63678721 has 8 divisors (see below), whose sum is σ = 64389024. Its totient is φ = 62972640.

The previous prime is 63678701. The next prime is 63678731. The reversal of 63678721 is 12787636.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-63678721 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (63678701) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 36141 + ... + 37861.

It is an arithmetic number, because the mean of its divisors is an integer number (8048628).

Almost surely, 2^63678721 is an apocalyptic number.

It is an amenable number.

63678721 is a deficient number, since it is larger than the sum of its proper divisors (710303).

63678721 is a wasteful number, since it uses less digits than its factorization.

63678721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2111.

The product of its digits is 84672, while the sum is 40.

The square root of 63678721 is about 7979.8947988053. The cubic root of 63678721 is about 399.3295456051.

The spelling of 63678721 in words is "sixty-three million, six hundred seventy-eight thousand, seven hundred twenty-one".