661257503 has 2 divisors, whose sum is σ = 661257504. Its totient is φ = 661257502.

The previous prime is 661257479. The next prime is 661257511. The reversal of 661257503 is 305752166.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 661257503 - 2¹² = 661253407 is a prime.

It is a super-2 number, since 2×661257503² = 874522970547590018, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (661257563) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330628751 + 330628752.

It is an arithmetic number, because the mean of its divisors is an integer number (330628752).

Almost surely, 2^661257503 is an apocalyptic number.

661257503 is a deficient number, since it is larger than the sum of its proper divisors (1).

661257503 is an equidigital number, since it uses as much as digits as its factorization.

661257503 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 37800, while the sum is 35.

The square root of 661257503 is about 25714.9276296862. The cubic root of 661257503 is about 871.2113758868.

The spelling of 661257503 in words is "six hundred sixty-one million, two hundred fifty-seven thousand, five hundred three".