623621 has 2 divisors, whose sum is σ = 623622. Its totient is φ = 623620.

The previous prime is 623617. The next prime is 623633. The reversal of 623621 is 126326.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 616225 + 7396 = 785^2 + 86^2 .

It is a cyclic number.

It is not a de Polignac number, because 623621 - 2² = 623617 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 623593 and 623602.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 623621.

It is not a weakly prime, because it can be changed into another prime (623641) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 311810 + 311811.

It is an arithmetic number, because the mean of its divisors is an integer number (311811).

2⁶²³⁶²¹ is an apocalyptic number.

It is an amenable number.

623621 is a deficient number, since it is larger than the sum of its proper divisors (1).

623621 is an equidigital number, since it uses as much as digits as its factorization.

623621 is an evil number, because the sum of its binary digits is even.

The product of its digits is 432, while the sum is 20.

The square root of 623621 is about 789.6967772506. The cubic root of 623621 is about 85.4358695143.

Adding to 623621 its reverse (126326), we get a palindrome (749947).

The spelling of 623621 in words is "six hundred twenty-three thousand, six hundred twenty-one".