20503997 has 2 divisors, whose sum is σ = 20503998. Its totient is φ = 20503996.

The previous prime is 20503993. The next prime is 20503999. The reversal of 20503997 is 79930502.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20484676 + 19321 = 4526^2 + 139^2 .

It is a cyclic number.

It is not a de Polignac number, because 20503997 - 2² = 20503993 is a prime.

Together with 20503999, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20503993) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10251998 + 10251999.

It is an arithmetic number, because the mean of its divisors is an integer number (10251999).

Almost surely, 2^20503997 is an apocalyptic number.

It is an amenable number.

20503997 is a deficient number, since it is larger than the sum of its proper divisors (1).

20503997 is an equidigital number, since it uses as much as digits as its factorization.

20503997 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 17010, while the sum is 35.

The square root of 20503997 is about 4528.1339423652. The cubic root of 20503997 is about 273.7029698959.

The spelling of 20503997 in words is "twenty million, five hundred three thousand, nine hundred ninety-seven".