661151563 has 2 divisors, whose sum is σ = 661151564. Its totient is φ = 661151562.

The previous prime is 661151549. The next prime is 661151567. The reversal of 661151563 is 365151166.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-661151563 is a prime.

It is not a weakly prime, because it can be changed into another prime (661151567) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330575781 + 330575782.

It is an arithmetic number, because the mean of its divisors is an integer number (330575782).

Almost surely, 2^661151563 is an apocalyptic number.

661151563 is a deficient number, since it is larger than the sum of its proper divisors (1).

661151563 is an equidigital number, since it uses as much as digits as its factorization.

661151563 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 16200, while the sum is 34.

The square root of 661151563 is about 25712.8676541532. The cubic root of 661151563 is about 871.1648478388.

The spelling of 661151563 in words is "six hundred sixty-one million, one hundred fifty-one thousand, five hundred sixty-three".