661558842 has 48 divisors (see below), whose sum is σ = 1734512832. Its totient is φ = 177897600.

The previous prime is 661558841. The next prime is 661558861. The reversal of 661558842 is 248855166.

661558842 is a `hidden beast` number, since 6 + 61 + 5 + 588 + 4 + 2 = 666.

It is a hoax number, since the sum of its digits (45) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (661558841) 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 in 23 ways as a sum of consecutive naturals, for example, 152284 + ... + 156567.

It is an arithmetic number, because the mean of its divisors is an integer number (36135684).

Almost surely, 2^661558842 is an apocalyptic number.

661558842 is an abundant number, since it is smaller than the sum of its proper divisors (1072953990).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

661558842 is a wasteful number, since it uses less digits than its factorization.

661558842 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 308883 (or 308880 counting only the distinct ones).

The product of its digits is 460800, while the sum is 45.

The square root of 661558842 is about 25720.7861854960. The cubic root of 661558842 is about 871.3436945346.

The spelling of 661558842 in words is "six hundred sixty-one million, five hundred fifty-eight thousand, eight hundred forty-two".