87166220685 has 16 divisors (see below), whose sum is σ = 139905916416. Its totient is φ = 46341996608.

The previous prime is 87166220681. The next prime is 87166220693. The reversal of 87166220685 is 58602266178.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 87166220685 - 2² = 87166220681 is a prime.

It is a super-2 number, since 2×87166220685² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (87166220681) 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, 9160989 + ... + 9170498.

It is an arithmetic number, because the mean of its divisors is an integer number (8744119776).

Almost surely, 2^87166220685 is an apocalyptic number.

It is an amenable number.

87166220685 is a deficient number, since it is larger than the sum of its proper divisors (52739695731).

87166220685 is a wasteful number, since it uses less digits than its factorization.

87166220685 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18331812.

The product of its (nonzero) digits is 1935360, while the sum is 51.

The spelling of 87166220685 in words is "eighty-seven billion, one hundred sixty-six million, two hundred twenty thousand, six hundred eighty-five".