687125661 has 4 divisors (see below), whose sum is σ = 916167552. Its totient is φ = 458083772.

The previous prime is 687125653. The next prime is 687125701. The reversal of 687125661 is 166521786.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 687125661 - 2³ = 687125653 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (687125561) 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, 114520941 + ... + 114520946.

It is an arithmetic number, because the mean of its divisors is an integer number (229041888).

Almost surely, 2^687125661 is an apocalyptic number.

It is an amenable number.

687125661 is a deficient number, since it is larger than the sum of its proper divisors (229041891).

687125661 is a wasteful number, since it uses less digits than its factorization.

687125661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 229041890.

The product of its digits is 120960, while the sum is 42.

The square root of 687125661 is about 26213.0818676477. The cubic root of 687125661 is about 882.4268672260.

It can be divided in two parts, 687125 and 661, that added together give a palindrome (687786).

The spelling of 687125661 in words is "six hundred eighty-seven million, one hundred twenty-five thousand, six hundred sixty-one".