661545655 has 16 divisors (see below), whose sum is σ = 799896384. Its totient is φ = 525226240.

The previous prime is 661545641. The next prime is 661545679. The reversal of 661545655 is 556545166.

It is not a de Polignac number, because 661545655 - 2¹¹ = 661543607 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 410862 + ... + 412468.

It is an arithmetic number, because the mean of its divisors is an integer number (49993524).

Almost surely, 2^661545655 is an apocalyptic number.

661545655 is a deficient number, since it is larger than the sum of its proper divisors (138350729).

661545655 is a wasteful number, since it uses less digits than its factorization.

661545655 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2186.

The product of its digits is 540000, while the sum is 43.

The square root of 661545655 is about 25720.5298351336. The cubic root of 661545655 is about 871.3379049334.

The spelling of 661545655 in words is "six hundred sixty-one million, five hundred forty-five thousand, six hundred fifty-five".