661513 has 2 divisors, whose sum is σ = 661514. Its totient is φ = 661512.

The previous prime is 661483. The next prime is 661517. The reversal of 661513 is 315166.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 652864 + 8649 = 808^2 + 93^2 .

It is a cyclic number.

It is not a de Polignac number, because 661513 - 2⁵ = 661481 is a prime.

It is not a weakly prime, because it can be changed into another prime (661517) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330756 + 330757.

It is an arithmetic number, because the mean of its divisors is an integer number (330757).

2⁶⁶¹⁵¹³ is an apocalyptic number.

It is an amenable number.

661513 is a deficient number, since it is larger than the sum of its proper divisors (1).

661513 is an equidigital number, since it uses as much as digits as its factorization.

661513 is an evil number, because the sum of its binary digits is even.

The product of its digits is 540, while the sum is 22.

The square root of 661513 is about 813.3344945347. The cubic root of 661513 is about 87.1323567799.

Adding to 661513 its reverse (315166), we get a palindrome (976679).

The spelling of 661513 in words is "six hundred sixty-one thousand, five hundred thirteen".