620561 has 2 divisors, whose sum is σ = 620562. Its totient is φ = 620560.

The previous prime is 620549. The next prime is 620567. The reversal of 620561 is 165026.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 555025 + 65536 = 745^2 + 256^2 .

It is a cyclic number.

It is not a de Polignac number, because 620561 - 2¹⁰ = 619537 is a prime.

It is a Chen prime.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 620561.

It is not a weakly prime, because it can be changed into another prime (620567) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 310280 + 310281.

It is an arithmetic number, because the mean of its divisors is an integer number (310281).

2⁶²⁰⁵⁶¹ is an apocalyptic number.

It is an amenable number.

620561 is a deficient number, since it is larger than the sum of its proper divisors (1).

620561 is an equidigital number, since it uses as much as digits as its factorization.

620561 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 360, while the sum is 20.

The square root of 620561 is about 787.7569422100. The cubic root of 620561 is about 85.2959006692.

Adding to 620561 its reverse (165026), we get a palindrome (785587).

Subtracting from 620561 its reverse (165026), we obtain a triangular number (455535 = T₉₅₄).

The spelling of 620561 in words is "six hundred twenty thousand, five hundred sixty-one".