1661438187 has 6 divisors (see below), whose sum is σ = 2399855172. Its totient is φ = 1107625452.

The previous prime is 1661438167. The next prime is 1661438201. The reversal of 1661438187 is 7818341661.

1661438187 is a `hidden beast` number, since 16 + 614 + 3 + 8 + 18 + 7 = 666.

It is not a de Polignac number, because 1661438187 - 2¹² = 1661434091 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1661438137) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 92302113 + ... + 92302130.

It is an arithmetic number, because the mean of its divisors is an integer number (399975862).

Almost surely, 2^1661438187 is an apocalyptic number.

1661438187 is a deficient number, since it is larger than the sum of its proper divisors (738416985).

1661438187 is a wasteful number, since it uses less digits than its factorization.

1661438187 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 184604249 (or 184604246 counting only the distinct ones).

The product of its digits is 193536, while the sum is 45.

The square root of 1661438187 is about 40760.7432096128. The cubic root of 1661438187 is about 1184.3899931473.

The spelling of 1661438187 in words is "one billion, six hundred sixty-one million, four hundred thirty-eight thousand, one hundred eighty-seven".