661012427 has 2 divisors, whose sum is σ = 661012428. Its totient is φ = 661012426.

The previous prime is 661012403. The next prime is 661012463. The reversal of 661012427 is 724210166.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-661012427 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 661012427.

It is not a weakly prime, because it can be changed into another prime (661012477) 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, 330506213 + 330506214.

It is an arithmetic number, because the mean of its divisors is an integer number (330506214).

Almost surely, 2^661012427 is an apocalyptic number.

661012427 is a deficient number, since it is larger than the sum of its proper divisors (1).

661012427 is an equidigital number, since it uses as much as digits as its factorization.

661012427 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4032, while the sum is 29.

The square root of 661012427 is about 25710.1619403690. The cubic root of 661012427 is about 871.1037328072.

The spelling of 661012427 in words is "six hundred sixty-one million, twelve thousand, four hundred twenty-seven".