687001949 has 4 divisors (see below), whose sum is σ = 687347964. Its totient is φ = 686655936.

The previous prime is 687001897. The next prime is 687001951. The reversal of 687001949 is 949100786.

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 210453049 + 476548900 = 14507^2 + 21830^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-687001949 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (687001969) 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, 170012 + ... + 174005.

It is an arithmetic number, because the mean of its divisors is an integer number (171836991).

Almost surely, 2^687001949 is an apocalyptic number.

It is an amenable number.

687001949 is a deficient number, since it is larger than the sum of its proper divisors (346015).

687001949 is a wasteful number, since it uses less digits than its factorization.

687001949 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 346014.

The product of its (nonzero) digits is 108864, while the sum is 44.

The square root of 687001949 is about 26210.7220236299. The cubic root of 687001949 is about 882.3739058580.

The spelling of 687001949 in words is "six hundred eighty-seven million, one thousand, nine hundred forty-nine".