661529787925166 has 16 divisors (see below), whose sum is σ = 1002625781755920. Its totient is φ = 327321882835200.

The previous prime is 661529787925133. The next prime is 661529787925187.

661529787925166 is nontrivially palindromic in base 10.

It is a super-2 number, since 2×661529787925166² (a number of 30 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 170281376 + ... + 174122963.

It is an arithmetic number, because the mean of its divisors is an integer number (62664111359745).

Almost surely, 2^{661529787925166} is an apocalyptic number.

661529787925166 is a deficient number, since it is larger than the sum of its proper divisors (341095993830754).

661529787925166 is a wasteful number, since it uses less digits than its factorization.

661529787925166 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 344414339.

The product of its digits is 4115059200, while the sum is 80.

The spelling of 661529787925166 in words is "six hundred sixty-one trillion, five hundred twenty-nine billion, seven hundred eighty-seven million, nine hundred twenty-five thousand, one hundred sixty-six".