1671686621 has 16 divisors (see below), whose sum is σ = 1938867840. Its totient is φ = 1426201920.

The previous prime is 1671686609. The next prime is 1671686657. The reversal of 1671686621 is 1266861761.

It is not a de Polignac number, because 1671686621 - 2¹⁴ = 1671670237 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1671686321) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 48926 + ... + 75743.

It is an arithmetic number, because the mean of its divisors is an integer number (121179240).

Almost surely, 2^1671686621 is an apocalyptic number.

1671686621 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1671686621 is a deficient number, since it is larger than the sum of its proper divisors (267181219).

1671686621 is a wasteful number, since it uses less digits than its factorization.

1671686621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 124756.

The product of its digits is 145152, while the sum is 44.

The square root of 1671686621 is about 40886.2644539704. The cubic root of 1671686621 is about 1186.8202711762.

The spelling of 1671686621 in words is "one billion, six hundred seventy-one million, six hundred eighty-six thousand, six hundred twenty-one".