63728126491 has 4 divisors (see below), whose sum is σ = 67476839832. Its totient is φ = 59979413152.

The previous prime is 63728126467. The next prime is 63728126513. The reversal of 63728126491 is 19462182736.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 63728126491 - 2³⁵ = 29368388123 is a prime.

It is a super-2 number, since 2×63728126491² (a number of 22 digits) contains 22 as substring.

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (63728126191) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1874356645 + ... + 1874356678.

It is an arithmetic number, because the mean of its divisors is an integer number (16869209958).

Almost surely, 2^63728126491 is an apocalyptic number.

63728126491 is a deficient number, since it is larger than the sum of its proper divisors (3748713341).

63728126491 is a wasteful number, since it uses less digits than its factorization.

63728126491 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3748713340.

The product of its digits is 870912, while the sum is 49.

The spelling of 63728126491 in words is "sixty-three billion, seven hundred twenty-eight million, one hundred twenty-six thousand, four hundred ninety-one".