1665413878 has 8 divisors (see below), whose sum is σ = 2629600920. Its totient is φ = 788880240.

The previous prime is 1665413863. The next prime is 1665413903. The reversal of 1665413878 is 8783145661.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 21913303 + ... + 21913378.

It is an arithmetic number, because the mean of its divisors is an integer number (328700115).

Almost surely, 2^1665413878 is an apocalyptic number.

1665413878 is a deficient number, since it is larger than the sum of its proper divisors (964187042).

1665413878 is a wasteful number, since it uses less digits than its factorization.

1665413878 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43826702.

The product of its digits is 967680, while the sum is 49.

The square root of 1665413878 is about 40809.4826970399. The cubic root of 1665413878 is about 1185.3339579913. Note that the first 3 decimals are identical.

The spelling of 1665413878 in words is "one billion, six hundred sixty-five million, four hundred thirteen thousand, eight hundred seventy-eight".