212805081 has 24 divisors (see below), whose sum is σ = 312294216. Its totient is φ = 139622400.

The previous prime is 212805077. The next prime is 212805083. The reversal of 212805081 is 180508212.

It can be written as a sum of positive squares in 4 ways, for example, as 13995081 + 198810000 = 3741^2 + 14100^2 .

It is not a de Polignac number, because 212805081 - 2² = 212805077 is a prime.

It is a super-2 number, since 2×212805081² = 90572004998833122, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (212805083) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 174831 + ... + 176043.

It is an arithmetic number, because the mean of its divisors is an integer number (13012259).

Almost surely, 2^212805081 is an apocalyptic number.

It is an amenable number.

212805081 is a deficient number, since it is larger than the sum of its proper divisors (99489135).

212805081 is a wasteful number, since it uses less digits than its factorization.

212805081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1513 (or 1510 counting only the distinct ones).

The product of its (nonzero) digits is 1280, while the sum is 27.

The square root of 212805081 is about 14587.8401759822. The cubic root of 212805081 is about 597.0270351300.

The spelling of 212805081 in words is "two hundred twelve million, eight hundred five thousand, eighty-one".