6477721987 has 4 divisors (see below), whose sum is σ = 7066605816. Its totient is φ = 5888838160.

The previous prime is 6477721981. The next prime is 6477721993. The reversal of 6477721987 is 7891277746.

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

It is an interprime number because it is at equal distance from previous prime (6477721981) and next prime (6477721993).

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-6477721987 is a prime.

It is a Smith number, since the sum of its digits (58) 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 (6477721981) 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, 294441898 + ... + 294441919.

It is an arithmetic number, because the mean of its divisors is an integer number (1766651454).

Almost surely, 2^6477721987 is an apocalyptic number.

6477721987 is a deficient number, since it is larger than the sum of its proper divisors (588883829).

6477721987 is a wasteful number, since it uses less digits than its factorization.

6477721987 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 588883828.

The product of its digits is 8297856, while the sum is 58.

The square root of 6477721987 is about 80484.2965242289. The cubic root of 6477721987 is about 1864.1210114225.

The spelling of 6477721987 in words is "six billion, four hundred seventy-seven million, seven hundred twenty-one thousand, nine hundred eighty-seven".