216572181 has 16 divisors (see below), whose sum is σ = 331065984. Its totient is φ = 123361344.

The previous prime is 216572171. The next prime is 216572189. The reversal of 216572181 is 181275612.

It is not a de Polignac number, because 216572181 - 2⁷ = 216572053 is a prime.

It is a super-2 number, since 2×216572181² = 93807019166193522, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216572189) 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, 9610 + ... + 22923.

It is an arithmetic number, because the mean of its divisors is an integer number (20691624).

Almost surely, 2^216572181 is an apocalyptic number.

216572181 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

216572181 is a deficient number, since it is larger than the sum of its proper divisors (114493803).

216572181 is a wasteful number, since it uses less digits than its factorization.

216572181 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32860.

The product of its digits is 6720, while the sum is 33.

The square root of 216572181 is about 14716.3915753829. The cubic root of 216572181 is about 600.5293301010.

The spelling of 216572181 in words is "two hundred sixteen million, five hundred seventy-two thousand, one hundred eighty-one".