661125403 has 2 divisors, whose sum is σ = 661125404. Its totient is φ = 661125402.

The previous prime is 661125397. The next prime is 661125407. The reversal of 661125403 is 304521166.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 661125403 - 2¹³ = 661117211 is a prime.

It is not a weakly prime, because it can be changed into another prime (661125407) 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, 330562701 + 330562702.

It is an arithmetic number, because the mean of its divisors is an integer number (330562702).

Almost surely, 2^661125403 is an apocalyptic number.

661125403 is a deficient number, since it is larger than the sum of its proper divisors (1).

661125403 is an equidigital number, since it uses as much as digits as its factorization.

661125403 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4320, while the sum is 28.

The square root of 661125403 is about 25712.3589544017. The cubic root of 661125403 is about 871.1533577991.

Adding to 661125403 its reverse (304521166), we get a palindrome (965646569).

The spelling of 661125403 in words is "six hundred sixty-one million, one hundred twenty-five thousand, four hundred three".