661245427 has 4 divisors (see below), whose sum is σ = 661745056. Its totient is φ = 660745800.

The previous prime is 661245373. The next prime is 661245449. The reversal of 661245427 is 724542166.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 724542166 = 2 ⋅362271083.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-661245427 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (661245227) 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 in 3 ways as a sum of consecutive naturals, for example, 247824 + ... + 250477.

It is an arithmetic number, because the mean of its divisors is an integer number (165436264).

Almost surely, 2^661245427 is an apocalyptic number.

661245427 is a deficient number, since it is larger than the sum of its proper divisors (499629).

661245427 is a wasteful number, since it uses less digits than its factorization.

661245427 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 499628.

The product of its digits is 80640, while the sum is 37.

The square root of 661245427 is about 25714.6928233646. The cubic root of 661245427 is about 871.2060724497.

The spelling of 661245427 in words is "six hundred sixty-one million, two hundred forty-five thousand, four hundred twenty-seven".