668690109 has 12 divisors (see below), whose sum is σ = 1007881056. Its totient is φ = 426410952.

The previous prime is 668690101. The next prime is 668690117. The reversal of 668690109 is 901096866.

It is an interprime number because it is at equal distance from previous prime (668690101) and next prime (668690117).

It is not a de Polignac number, because 668690109 - 2³ = 668690101 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (668690101) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1614987 + ... + 1615400.

It is an arithmetic number, because the mean of its divisors is an integer number (83990088).

Almost surely, 2^668690109 is an apocalyptic number.

668690109 is a gapful number since it is divisible by the number (69) formed by its first and last digit.

It is an amenable number.

668690109 is a deficient number, since it is larger than the sum of its proper divisors (339190947).

668690109 is a wasteful number, since it uses less digits than its factorization.

668690109 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3230416 (or 3230413 counting only the distinct ones).

The product of its (nonzero) digits is 139968, while the sum is 45.

The square root of 668690109 is about 25859.0430797429. The cubic root of 668690109 is about 874.4633919087.

The spelling of 668690109 in words is "six hundred sixty-eight million, six hundred ninety thousand, one hundred nine".