624721 has 2 divisors, whose sum is σ = 624722. Its totient is φ = 624720.

The previous prime is 624709. The next prime is 624727. The reversal of 624721 is 127426.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 555025 + 69696 = 745^2 + 264^2 .

It is a cyclic number.

It is not a de Polignac number, because 624721 - 2⁷ = 624593 is a prime.

It is an Ulam number.

624721 is a lucky number.

It is a nialpdrome in base 16.

It is a junction number, because it is equal to n+sod(n) for n = 624692 and 624701.

It is not a weakly prime, because it can be changed into another prime (624727) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 312360 + 312361.

It is an arithmetic number, because the mean of its divisors is an integer number (312361).

2⁶²⁴⁷²¹ is an apocalyptic number.

It is an amenable number.

624721 is a deficient number, since it is larger than the sum of its proper divisors (1).

624721 is an equidigital number, since it uses as much as digits as its factorization.

624721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 672, while the sum is 22.

The square root of 624721 is about 790.3929402519. The cubic root of 624721 is about 85.4860732193.

The spelling of 624721 in words is "six hundred twenty-four thousand, seven hundred twenty-one".