677991 has 8 divisors (see below), whose sum is σ = 935280. Its totient is φ = 436352.

The previous prime is 677983. The next prime is 678023. The reversal of 677991 is 199776.

677991 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 677991 - 2³ = 677983 is a prime.

It is an Ulam number.

677991 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (677791) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3810 + ... + 3983.

It is an arithmetic number, because the mean of its divisors is an integer number (116910).

2⁶⁷⁷⁹⁹¹ is an apocalyptic number.

677991 is a deficient number, since it is larger than the sum of its proper divisors (257289).

677991 is a wasteful number, since it uses less digits than its factorization.

677991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7825.

The product of its digits is 23814, while the sum is 39.

The square root of 677991 is about 823.4020888970. The cubic root of 677991 is about 87.8499077165.

Adding to 677991 its sum of digits (39), we get a triangular number (678030 = T₁₁₆₄).

The spelling of 677991 in words is "six hundred seventy-seven thousand, nine hundred ninety-one".