166654519821 has 32 divisors (see below), whose sum is σ = 248571073920. Its totient is φ = 110349931392.

The previous prime is 166654519783. The next prime is 166654519877. The reversal of 166654519821 is 128915456661.

It is a happy number.

It is not a de Polignac number, because 166654519821 - 2⁷ = 166654519693 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (166654519121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 7281031 + ... + 7303883.

It is an arithmetic number, because the mean of its divisors is an integer number (7767846060).

Almost surely, 2^166654519821 is an apocalyptic number.

It is an amenable number.

166654519821 is a deficient number, since it is larger than the sum of its proper divisors (81916554099).

166654519821 is a wasteful number, since it uses less digits than its factorization.

166654519821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24682 (or 24676 counting only the distinct ones).

The product of its digits is 3110400, while the sum is 54.

It can be divided in two parts, 1666545 and 19821, that added together give a triangular number (1686366 = T₁₈₃₆).

The spelling of 166654519821 in words is "one hundred sixty-six billion, six hundred fifty-four million, five hundred nineteen thousand, eight hundred twenty-one".