1639681669 has 8 divisors (see below), whose sum is σ = 1662436160. Its totient is φ = 1617084000.

The previous prime is 1639681639. The next prime is 1639681679. The reversal of 1639681669 is 9661869361.

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

It is a cyclic number.

It is not a de Polignac number, because 1639681669 - 2⁷ = 1639681541 is a prime.

It is a super-2 number, since 2×1639681669² = 5377111951309251122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1639681639) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 18072 + ... + 60049.

It is an arithmetic number, because the mean of its divisors is an integer number (207804520).

Almost surely, 2^1639681669 is an apocalyptic number.

It is an amenable number.

1639681669 is a deficient number, since it is larger than the sum of its proper divisors (22754491).

1639681669 is a wasteful number, since it uses less digits than its factorization.

1639681669 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 78411.

The product of its digits is 2519424, while the sum is 55.

The square root of 1639681669 is about 40492.9829600142. The cubic root of 1639681669 is about 1179.1974023700.

The spelling of 1639681669 in words is "one billion, six hundred thirty-nine million, six hundred eighty-one thousand, six hundred sixty-nine".