661166055 has 24 divisors (see below), whose sum is σ = 1250205840. Its totient is φ = 320565120.

The previous prime is 661166053. The next prime is 661166063. The reversal of 661166055 is 550661166.

It is not a de Polignac number, because 661166055 - 2¹ = 661166053 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661166053) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 667350 + ... + 668339.

It is an arithmetic number, because the mean of its divisors is an integer number (52091910).

Almost surely, 2^661166055 is an apocalyptic number.

661166055 is a deficient number, since it is larger than the sum of its proper divisors (589039785).

661166055 is a wasteful number, since it uses less digits than its factorization.

661166055 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1335711 (or 1335708 counting only the distinct ones).

The product of its (nonzero) digits is 32400, while the sum is 36.

The square root of 661166055 is about 25713.1494570385. The cubic root of 661166055 is about 871.1712129092.

The spelling of 661166055 in words is "six hundred sixty-one million, one hundred sixty-six thousand, fifty-five".