166521403534641 has 16 divisors (see below), whose sum is σ = 222060429972288. Its totient is φ = 110998324236800.

The previous prime is 166521403534631. The next prime is 166521403534693. The reversal of 166521403534641 is 146435304125661.

It is a cyclic number.

It is not a de Polignac number, because 166521403534641 - 2¹⁷ = 166521403403569 is a prime.

It is not an unprimeable number, because it can be changed into a prime (166521403534631) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 628532521 + ... + 628797401.

It is an arithmetic number, because the mean of its divisors is an integer number (13878776873268).

Almost surely, 2^{166521403534641} is an apocalyptic number.

It is an amenable number.

166521403534641 is a deficient number, since it is larger than the sum of its proper divisors (55539026437647).

166521403534641 is a wasteful number, since it uses less digits than its factorization.

166521403534641 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 294192.

The product of its (nonzero) digits is 6220800, while the sum is 51.

The spelling of 166521403534641 in words is "one hundred sixty-six trillion, five hundred twenty-one billion, four hundred three million, five hundred thirty-four thousand, six hundred forty-one".