1663787915 has 16 divisors (see below), whose sum is σ = 2193004800. Its totient is φ = 1206149472.

The previous prime is 1663787903. The next prime is 1663787963. The reversal of 1663787915 is 5197873661.

It is a cyclic number.

It is not a de Polignac number, because 1663787915 - 2²⁰ = 1662739339 is a prime.

It is a super-3 number, since 3×1663787915³ (a number of 29 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

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, 378545 + ... + 382914.

It is an arithmetic number, because the mean of its divisors is an integer number (137062800).

Almost surely, 2^1663787915 is an apocalyptic number.

1663787915 is a deficient number, since it is larger than the sum of its proper divisors (529216885).

1663787915 is a wasteful number, since it uses less digits than its factorization.

1663787915 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 761506.

The product of its digits is 1905120, while the sum is 53.

The square root of 1663787915 is about 40789.5564452471. The cubic root of 1663787915 is about 1184.9480805942.

The spelling of 1663787915 in words is "one billion, six hundred sixty-three million, seven hundred eighty-seven thousand, nine hundred fifteen".