661355587 has 2 divisors, whose sum is σ = 661355588. Its totient is φ = 661355586.

The previous prime is 661355561. The next prime is 661355663. The reversal of 661355587 is 785553166.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 661355587 - 2²⁷ = 527137859 is a prime.

It is a super-2 number, since 2×661355587² = 874782424912229138, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (661355507) 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, 330677793 + 330677794.

It is an arithmetic number, because the mean of its divisors is an integer number (330677794).

Almost surely, 2^661355587 is an apocalyptic number.

661355587 is a deficient number, since it is larger than the sum of its proper divisors (1).

661355587 is an equidigital number, since it uses as much as digits as its factorization.

661355587 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 756000, while the sum is 46.

The square root of 661355587 is about 25716.8347002503. The cubic root of 661355587 is about 871.2544492087.

The spelling of 661355587 in words is "six hundred sixty-one million, three hundred fifty-five thousand, five hundred eighty-seven".