661565151 has 20 divisors (see below), whose sum is σ = 1064285992. Its totient is φ = 407116368.

The previous prime is 661565147. The next prime is 661565153. The reversal of 661565151 is 151565166.

It is not a de Polignac number, because 661565151 - 2² = 661565147 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661565153) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 313081 + ... + 315186.

Almost surely, 2^661565151 is an apocalyptic number.

661565151 is a deficient number, since it is larger than the sum of its proper divisors (402720841).

661565151 is a wasteful number, since it uses less digits than its factorization.

661565151 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 628292 (or 628283 counting only the distinct ones).

The product of its digits is 27000, while the sum is 36.

The square root of 661565151 is about 25720.9088291996. The cubic root of 661565151 is about 871.3464644016.

The spelling of 661565151 in words is "six hundred sixty-one million, five hundred sixty-five thousand, one hundred fifty-one".