645993503 has 2 divisors, whose sum is σ = 645993504. Its totient is φ = 645993502.

The previous prime is 645993463. The next prime is 645993527. The reversal of 645993503 is 305399546.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-645993503 is a prime.

It is a super-2 number, since 2×645993503² = 834615211836422018, which contains 22 as substring.

It is a Chen prime.

It is equal to p_33595946 and since 645993503 and 33595946 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (645993703) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322996751 + 322996752.

It is an arithmetic number, because the mean of its divisors is an integer number (322996752).

Almost surely, 2^645993503 is an apocalyptic number.

645993503 is a deficient number, since it is larger than the sum of its proper divisors (1).

645993503 is an equidigital number, since it uses as much as digits as its factorization.

645993503 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 437400, while the sum is 44.

The square root of 645993503 is about 25416.4022434333. The cubic root of 645993503 is about 864.4556491325.

The spelling of 645993503 in words is "six hundred forty-five million, nine hundred ninety-three thousand, five hundred three".