661015603 has 2 divisors, whose sum is σ = 661015604. Its totient is φ = 661015602.

The previous prime is 661015577. The next prime is 661015633. The reversal of 661015603 is 306510166.

661015603 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 661015603 - 2²¹ = 658918451 is a prime.

It is not a weakly prime, because it can be changed into another prime (661015633) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330507801 + 330507802.

It is an arithmetic number, because the mean of its divisors is an integer number (330507802).

Almost surely, 2^661015603 is an apocalyptic number.

661015603 is a deficient number, since it is larger than the sum of its proper divisors (1).

661015603 is an equidigital number, since it uses as much as digits as its factorization.

661015603 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3240, while the sum is 28.

The square root of 661015603 is about 25710.2237057557. The cubic root of 661015603 is about 871.1051279504.

Adding to 661015603 its reverse (306510166), we get a palindrome (967525769).

The spelling of 661015603 in words is "six hundred sixty-one million, fifteen thousand, six hundred three".