63721821 has 8 divisors (see below), whose sum is σ = 85013280. Its totient is φ = 42455792.

The previous prime is 63721813. The next prime is 63721871. The reversal of 63721821 is 12812736.

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

It is a cyclic number.

It is not a de Polignac number, because 63721821 - 2³ = 63721813 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (63721811) 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, 571 + ... + 11303.

It is an arithmetic number, because the mean of its divisors is an integer number (10626660).

Almost surely, 2^63721821 is an apocalyptic number.

It is an amenable number.

63721821 is a deficient number, since it is larger than the sum of its proper divisors (21291459).

63721821 is a wasteful number, since it uses less digits than its factorization.

63721821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12715.

The product of its digits is 4032, while the sum is 30.

The square root of 63721821 is about 7982.5948788599. The cubic root of 63721821 is about 399.4196187179.

The spelling of 63721821 in words is "sixty-three million, seven hundred twenty-one thousand, eight hundred twenty-one".