661428505824166 has 8 divisors (see below), whose sum is σ = 992147085445824. Its totient is φ = 330712810675560.

The previous prime is 661428505824139. The next prime is 661428505824311.

661428505824166 is nontrivially palindromic in base 10.

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

It is a junction number, because it is equal to n+sod(n) for n = 661428505824098 and 661428505824107.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 720544905 + ... + 721462276.

It is an arithmetic number, because the mean of its divisors is an integer number (124018385680728).

Almost surely, 2^{661428505824166} is an apocalyptic number.

661428505824166 is a deficient number, since it is larger than the sum of its proper divisors (330718579621658).

661428505824166 is a wasteful number, since it uses less digits than its factorization.

661428505824166 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1442236526.

The product of its (nonzero) digits is 132710400, while the sum is 64.

The spelling of 661428505824166 in words is "six hundred sixty-one trillion, four hundred twenty-eight billion, five hundred five million, eight hundred twenty-four thousand, one hundred sixty-six".