900505621 has 2 divisors, whose sum is σ = 900505622. Its totient is φ = 900505620.

The previous prime is 900505603. The next prime is 900505633. The reversal of 900505621 is 126505009.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 759608721 + 140896900 = 27561^2 + 11870^2 .

It is an emirp because it is prime and its reverse (126505009) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 900505621 - 2⁷ = 900505493 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 900505621.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (900505681) 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, 450252810 + 450252811.

It is an arithmetic number, because the mean of its divisors is an integer number (450252811).

Almost surely, 2^900505621 is an apocalyptic number.

It is an amenable number.

900505621 is a deficient number, since it is larger than the sum of its proper divisors (1).

900505621 is an equidigital number, since it uses as much as digits as its factorization.

900505621 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2700, while the sum is 28.

The square root of 900505621 is about 30008.4258334222. The cubic root of 900505621 is about 965.6701550938.

It can be divided in two parts, 900 and 505621, that added together give a triangular number (506521 = T₁₀₀₆).

The spelling of 900505621 in words is "nine hundred million, five hundred five thousand, six hundred twenty-one".