20503993 has 2 divisors, whose sum is σ = 20503994. Its totient is φ = 20503992.

The previous prime is 20503981. The next prime is 20503997. The reversal of 20503993 is 39930502.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19607184 + 896809 = 4428^2 + 947^2 .

It is a cyclic number.

It is not a de Polignac number, because 20503993 - 2⁵ = 20503961 is a prime.

It is not a weakly prime, because it can be changed into another prime (20503997) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10251996 + 10251997.

It is an arithmetic number, because the mean of its divisors is an integer number (10251997).

Almost surely, 2^20503993 is an apocalyptic number.

It is an amenable number.

20503993 is a deficient number, since it is larger than the sum of its proper divisors (1).

20503993 is an equidigital number, since it uses as much as digits as its factorization.

20503993 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 7290, while the sum is 31.

The square root of 20503993 is about 4528.1335006822. The cubic root of 20503993 is about 273.7029520975.

The spelling of 20503993 in words is "twenty million, five hundred three thousand, nine hundred ninety-three".