8537781321 has 16 divisors (see below), whose sum is σ = 12764611200. Its totient is φ = 5639633424.

The previous prime is 8537781277. The next prime is 8537781377. The reversal of 8537781321 is 1231877358.

8537781321 is a `hidden beast` number, since 8 + 537 + 7 + 81 + 32 + 1 = 666.

It is not a de Polignac number, because 8537781321 - 2²² = 8533587017 is a prime.

It is not an unprimeable number, because it can be changed into a prime (8537701321) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1447581 + ... + 1453466.

It is an arithmetic number, because the mean of its divisors is an integer number (797788200).

Almost surely, 2^8537781321 is an apocalyptic number.

It is an amenable number.

8537781321 is a deficient number, since it is larger than the sum of its proper divisors (4226829879).

8537781321 is a wasteful number, since it uses less digits than its factorization.

8537781321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2901165 (or 2901159 counting only the distinct ones).

The product of its digits is 282240, while the sum is 45.

The square root of 8537781321 is about 92400.1153733046. The cubic root of 8537781321 is about 2043.8468137624.

The spelling of 8537781321 in words is "eight billion, five hundred thirty-seven million, seven hundred eighty-one thousand, three hundred twenty-one".