681387145 has 4 divisors (see below), whose sum is σ = 817664580. Its totient is φ = 545109712.

The previous prime is 681387143. The next prime is 681387151. The reversal of 681387145 is 541783186.

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

It can be written as a sum of positive squares in 2 ways, for example, as 429815824 + 251571321 = 20732^2 + 15861^2 .

It is a cyclic number.

It is not a de Polignac number, because 681387145 - 2¹ = 681387143 is a prime.

It is not an unprimeable number, because it can be changed into a prime (681387143) 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, 68138710 + ... + 68138719.

It is an arithmetic number, because the mean of its divisors is an integer number (204416145).

Almost surely, 2^681387145 is an apocalyptic number.

It is an amenable number.

681387145 is a deficient number, since it is larger than the sum of its proper divisors (136277435).

681387145 is a wasteful number, since it uses less digits than its factorization.

681387145 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 136277434.

The product of its digits is 161280, while the sum is 43.

The square root of 681387145 is about 26103.3933617834. The cubic root of 681387145 is about 879.9634734322.

The spelling of 681387145 in words is "six hundred eighty-one million, three hundred eighty-seven thousand, one hundred forty-five".