251623 has 2 divisors, whose sum is σ = 251624. Its totient is φ = 251622.

The previous prime is 251621. The next prime is 251639. The reversal of 251623 is 326152.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 251623 - 2¹ = 251621 is a prime.

Together with 251621, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 251623.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (251621) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 125811 + 125812.

It is an arithmetic number, because the mean of its divisors is an integer number (125812).

2²⁵¹⁶²³ is an apocalyptic number.

251623 is a deficient number, since it is larger than the sum of its proper divisors (1).

251623 is an equidigital number, since it uses as much as digits as its factorization.

251623 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 360, while the sum is 19.

The square root of 251623 is about 501.6203743868. The cubic root of 251623 is about 63.1320820078.

Adding to 251623 its reverse (326152), we get a palindrome (577775).

Subtracting 251623 from its reverse (326152), we obtain a square (74529 = 273²).

The spelling of 251623 in words is "two hundred fifty-one thousand, six hundred twenty-three".