624991 has 4 divisors (see below), whose sum is σ = 645184. Its totient is φ = 604800.

The previous prime is 624983. The next prime is 624997. The reversal of 624991 is 199426.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 199426 = 2 ⋅99713.

It is a cyclic number.

It is not a de Polignac number, because 624991 - 2³ = 624983 is a prime.

It is a super-2 number, since 2×624991² = 781227500162, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (31), and also a Moran number because the ratio is a prime number: 20161 = 624991 / (6 + 2 + 4 + 9 + 9 + 1).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (624997) 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, 10050 + ... + 10111.

It is an arithmetic number, because the mean of its divisors is an integer number (161296).

2⁶²⁴⁹⁹¹ is an apocalyptic number.

624991 is a deficient number, since it is larger than the sum of its proper divisors (20193).

624991 is a wasteful number, since it uses less digits than its factorization.

624991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20192.

The product of its digits is 3888, while the sum is 31.

The square root of 624991 is about 790.5637229218. The cubic root of 624991 is about 85.4983869376.

It can be divided in two parts, 62499 and 1, that added together give a square (62500 = 250²).

The spelling of 624991 in words is "six hundred twenty-four thousand, nine hundred ninety-one".