63996921 has 24 divisors (see below), whose sum is σ = 97735040. Its totient is φ = 40240800.

The previous prime is 63996899. The next prime is 63996929. The reversal of 63996921 is 12969936.

It is a happy number.

63996921 is a `hidden beast` number, since 639 + 9 + 6 + 9 + 2 + 1 = 666.

It is not a de Polignac number, because 63996921 - 2¹¹ = 63994873 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (63996929) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 45651 + ... + 47031.

Almost surely, 2^63996921 is an apocalyptic number.

It is an amenable number.

63996921 is a deficient number, since it is larger than the sum of its proper divisors (33738119).

63996921 is a wasteful number, since it uses less digits than its factorization.

63996921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1677 (or 1674 counting only the distinct ones).

The product of its digits is 157464, while the sum is 45.

The square root of 63996921 is about 7999.8075601854. The cubic root of 63996921 is about 399.9935853138.

The spelling of 63996921 in words is "sixty-three million, nine hundred ninety-six thousand, nine hundred twenty-one".