63987981 has 8 divisors (see below), whose sum is σ = 85441824. Its totient is φ = 42596400.

The previous prime is 63987967. The next prime is 63988031. The reversal of 63987981 is 18978936.

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

It is not a de Polignac number, because 63987981 - 2¹⁰ = 63986957 is a prime.

It is a super-2 number, since 2×63987981² = 8188923424912722, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (63987941) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 13111 + ... + 17316.

It is an arithmetic number, because the mean of its divisors is an integer number (10680228).

Almost surely, 2^63987981 is an apocalyptic number.

It is an amenable number.

63987981 is a deficient number, since it is larger than the sum of its proper divisors (21453843).

63987981 is a wasteful number, since it uses less digits than its factorization.

63987981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31131.

The product of its digits is 653184, while the sum is 51.

The square root of 63987981 is about 7999.2487772290. The cubic root of 63987981 is about 399.9749588491.

The spelling of 63987981 in words is "sixty-three million, nine hundred eighty-seven thousand, nine hundred eighty-one".