642083921 has 2 divisors, whose sum is σ = 642083922. Its totient is φ = 642083920.

The previous prime is 642083909. The next prime is 642083941. The reversal of 642083921 is 129380246.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 589955521 + 52128400 = 24289^2 + 7220^2 .

It is a cyclic number.

It is not a de Polignac number, because 642083921 - 2¹⁰ = 642082897 is a prime.

It is not a weakly prime, because it can be changed into another prime (642083941) 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, 321041960 + 321041961.

It is an arithmetic number, because the mean of its divisors is an integer number (321041961).

Almost surely, 2^642083921 is an apocalyptic number.

It is an amenable number.

642083921 is a deficient number, since it is larger than the sum of its proper divisors (1).

642083921 is an equidigital number, since it uses as much as digits as its factorization.

642083921 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 20736, while the sum is 35.

The square root of 642083921 is about 25339.3749133636. The cubic root of 642083921 is about 862.7082109106.

The spelling of 642083921 in words is "six hundred forty-two million, eighty-three thousand, nine hundred twenty-one".