661127563 has 2 divisors, whose sum is σ = 661127564. Its totient is φ = 661127562.

The previous prime is 661127561. The next prime is 661127609. The reversal of 661127563 is 365721166.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 661127563 - 2¹ = 661127561 is a prime.

Together with 661127561, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (661127561) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330563781 + 330563782.

It is an arithmetic number, because the mean of its divisors is an integer number (330563782).

Almost surely, 2^661127563 is an apocalyptic number.

661127563 is a deficient number, since it is larger than the sum of its proper divisors (1).

661127563 is an equidigital number, since it uses as much as digits as its factorization.

661127563 is an evil number, because the sum of its binary digits is even.

The product of its digits is 45360, while the sum is 37.

The square root of 661127563 is about 25712.4009575146. The cubic root of 661127563 is about 871.1543065295.

The spelling of 661127563 in words is "six hundred sixty-one million, one hundred twenty-seven thousand, five hundred sixty-three".