681642587 has 4 divisors (see below), whose sum is σ = 682100640. Its totient is φ = 681184536.

The previous prime is 681642583. The next prime is 681642629. The reversal of 681642587 is 785246186.

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 681642587 - 2² = 681642583 is a prime.

It is a super-3 number, since 3×681642587³ (a number of 27 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (681642583) 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, 226787 + ... + 229772.

It is an arithmetic number, because the mean of its divisors is an integer number (170525160).

Almost surely, 2^681642587 is an apocalyptic number.

681642587 is a deficient number, since it is larger than the sum of its proper divisors (458053).

681642587 is a wasteful number, since it uses less digits than its factorization.

681642587 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 458052.

The product of its digits is 645120, while the sum is 47.

The square root of 681642587 is about 26108.2857920623. The cubic root of 681642587 is about 880.0734214739.

The spelling of 681642587 in words is "six hundred eighty-one million, six hundred forty-two thousand, five hundred eighty-seven".