661355271 has 36 divisors (see below), whose sum is σ = 1031075136. Its totient is φ = 408038400.

The previous prime is 661355269. The next prime is 661355309. The reversal of 661355271 is 172553166.

It is not a de Polignac number, because 661355271 - 2¹ = 661355269 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661355221) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 145351 + ... + 149831.

It is an arithmetic number, because the mean of its divisors is an integer number (28640976).

Almost surely, 2^661355271 is an apocalyptic number.

661355271 is a deficient number, since it is larger than the sum of its proper divisors (369719865).

661355271 is a wasteful number, since it uses less digits than its factorization.

661355271 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4564 (or 4538 counting only the distinct ones).

The product of its digits is 37800, while the sum is 36.

The square root of 661355271 is about 25716.8285564142. The cubic root of 661355271 is about 871.2543104450.

The spelling of 661355271 in words is "six hundred sixty-one million, three hundred fifty-five thousand, two hundred seventy-one".