661013503 has 2 divisors, whose sum is σ = 661013504. Its totient is φ = 661013502.

The previous prime is 661013471. The next prime is 661013519. The reversal of 661013503 is 305310166.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 661013503 - 2⁵ = 661013471 is a prime.

It is a super-2 number, since 2×661013503² = 873877702296662018, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (661013543) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330506751 + 330506752.

It is an arithmetic number, because the mean of its divisors is an integer number (330506752).

Almost surely, 2^661013503 is an apocalyptic number.

661013503 is a deficient number, since it is larger than the sum of its proper divisors (1).

661013503 is an equidigital number, since it uses as much as digits as its factorization.

661013503 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1620, while the sum is 25.

The square root of 661013503 is about 25710.1828659385. The cubic root of 661013503 is about 871.1042054696.

Adding to 661013503 its reverse (305310166), we get a palindrome (966323669).

The spelling of 661013503 in words is "six hundred sixty-one million, thirteen thousand, five hundred three".