688149893 has 4 divisors (see below), whose sum is σ = 688300140. Its totient is φ = 687999648.

The previous prime is 688149887. The next prime is 688149907. The reversal of 688149893 is 398941886.

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 125843524 + 562306369 = 11218^2 + 23713^2 .

It is a cyclic number.

It is not a de Polignac number, because 688149893 - 2⁶ = 688149829 is a prime.

It is a super-2 number, since 2×688149893² = 947100550471822898, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (688149823) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 68030 + ... + 77487.

It is an arithmetic number, because the mean of its divisors is an integer number (172075035).

Almost surely, 2^688149893 is an apocalyptic number.

It is an amenable number.

688149893 is a deficient number, since it is larger than the sum of its proper divisors (150247).

688149893 is a wasteful number, since it uses less digits than its factorization.

688149893 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 150246.

The product of its digits is 2985984, while the sum is 56.

The square root of 688149893 is about 26232.6112501215. The cubic root of 688149893 is about 882.8650991166.

The spelling of 688149893 in words is "six hundred eighty-eight million, one hundred forty-nine thousand, eight hundred ninety-three".