1966638505 has 16 divisors (see below), whose sum is σ = 2544704064. Its totient is φ = 1450457280.

The previous prime is 1966638461. The next prime is 1966638547. The reversal of 1966638505 is 5058366691.

It is a happy number.

It is not a de Polignac number, because 1966638505 - 2¹¹ = 1966636457 is a prime.

It is a Duffinian 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, 34062 + ... + 71368.

It is an arithmetic number, because the mean of its divisors is an integer number (159044004).

Almost surely, 2^1966638505 is an apocalyptic number.

It is an amenable number.

1966638505 is a deficient number, since it is larger than the sum of its proper divisors (578065559).

1966638505 is a wasteful number, since it uses less digits than its factorization.

1966638505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 38136.

The product of its (nonzero) digits is 1166400, while the sum is 49.

The square root of 1966638505 is about 44346.7981369569. The cubic root of 1966638505 is about 1252.8762577037.

The spelling of 1966638505 in words is "one billion, nine hundred sixty-six million, six hundred thirty-eight thousand, five hundred five".