1665640415 has 16 divisors (see below), whose sum is σ = 2105313120. Its totient is φ = 1261572480.

The previous prime is 1665640397. The next prime is 1665640469. The reversal of 1665640415 is 5140465661.

It is a happy number.

It is not a de Polignac number, because 1665640415 - 2¹⁴ = 1665624031 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 173645 + ... + 182985.

It is an arithmetic number, because the mean of its divisors is an integer number (131582070).

Almost surely, 2^1665640415 is an apocalyptic number.

1665640415 is a deficient number, since it is larger than the sum of its proper divisors (439672705).

1665640415 is a wasteful number, since it uses less digits than its factorization.

1665640415 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11242.

The product of its (nonzero) digits is 86400, while the sum is 38.

The square root of 1665640415 is about 40812.2581462972. The cubic root of 1665640415 is about 1185.3877003529.

The spelling of 1665640415 in words is "one billion, six hundred sixty-five million, six hundred forty thousand, four hundred fifteen".