63739981 has 4 divisors (see below), whose sum is σ = 64691392. Its totient is φ = 62788572.

The previous prime is 63739967. The next prime is 63739993. The reversal of 63739981 is 18993736.

63739981 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 63739981 - 2¹⁵ = 63707213 is a prime.

It is a super-2 number, since 2×63739981² = 8125570355760722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (63739381) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 475605 + ... + 475738.

It is an arithmetic number, because the mean of its divisors is an integer number (16172848).

Almost surely, 2^63739981 is an apocalyptic number.

It is an amenable number.

63739981 is a deficient number, since it is larger than the sum of its proper divisors (951411).

63739981 is an equidigital number, since it uses as much as digits as its factorization.

63739981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 951410.

The product of its digits is 244944, while the sum is 46.

The square root of 63739981 is about 7983.7322725653. The cubic root of 63739981 is about 399.4575584755.

The spelling of 63739981 in words is "sixty-three million, seven hundred thirty-nine thousand, nine hundred eighty-one".