625991 has 8 divisors (see below), whose sum is σ = 692064. Its totient is φ = 563200.

The previous prime is 625979. The next prime is 625997. The reversal of 625991 is 199526.

625991 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 625991 - 2⁶ = 625927 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 (625997) 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, 410 + ... + 1191.

It is an arithmetic number, because the mean of its divisors is an integer number (86508).

2⁶²⁵⁹⁹¹ is an apocalyptic number.

625991 is a deficient number, since it is larger than the sum of its proper divisors (66073).

625991 is a wasteful number, since it uses less digits than its factorization.

625991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1641.

The product of its digits is 4860, while the sum is 32.

The square root of 625991 is about 791.1959302221. The cubic root of 625991 is about 85.5439624353.

The spelling of 625991 in words is "six hundred twenty-five thousand, nine hundred ninety-one".