166521403535051 has 4 divisors (see below), whose sum is σ = 168077678334552. Its totient is φ = 164965128735552.

The previous prime is 166521403534987. The next prime is 166521403535171. The reversal of 166521403535051 is 150535304125661.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 166521403535051 - 2⁶ = 166521403534987 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 166521403534987 and 166521403535005.

It is not an unprimeable number, because it can be changed into a prime (166521403535351) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 778137399590 + ... + 778137399803.

It is an arithmetic number, because the mean of its divisors is an integer number (42019419583638).

Almost surely, 2^{166521403535051} is an apocalyptic number.

166521403535051 is a deficient number, since it is larger than the sum of its proper divisors (1556274799501).

166521403535051 is a wasteful number, since it uses less digits than its factorization.

166521403535051 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1556274799500.

The product of its (nonzero) digits is 1620000, while the sum is 47.

The spelling of 166521403535051 in words is "one hundred sixty-six trillion, five hundred twenty-one billion, four hundred three million, five hundred thirty-five thousand, fifty-one".