87212181 has 16 divisors (see below), whose sum is σ = 133068800. Its totient is φ = 49770288.

The previous prime is 87212161. The next prime is 87212183. The reversal of 87212181 is 18121278.

It is a happy number.

It is not a de Polignac number, because 87212181 - 2⁵ = 87212149 is a prime.

It is a super-2 number, since 2×87212181² = 15211929029553522, which contains 22 as substring.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (87212183) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 17040 + ... + 21558.

It is an arithmetic number, because the mean of its divisors is an integer number (8316800).

Almost surely, 2^87212181 is an apocalyptic number.

It is an amenable number.

87212181 is a deficient number, since it is larger than the sum of its proper divisors (45856619).

87212181 is a wasteful number, since it uses less digits than its factorization.

87212181 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5448.

The product of its digits is 1792, while the sum is 30.

The square root of 87212181 is about 9338.7462220579. The cubic root of 87212181 is about 443.4646935191.

The spelling of 87212181 in words is "eighty-seven million, two hundred twelve thousand, one hundred eighty-one".