213444981 has 12 divisors (see below), whose sum is σ = 310664640. Its totient is φ = 141209640.

The previous prime is 213444977. The next prime is 213444997. The reversal of 213444981 is 189444312.

It is a happy number.

213444981 is a `hidden beast` number, since 2 + 134 + 449 + 81 = 666.

It is not a de Polignac number, because 213444981 - 2² = 213444977 is a prime.

It is a super-2 number, since 2×213444981² = 91117519828180722, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (213442981) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 89341 + ... + 91698.

It is an arithmetic number, because the mean of its divisors is an integer number (25888720).

Almost surely, 2^213444981 is an apocalyptic number.

It is an amenable number.

213444981 is a deficient number, since it is larger than the sum of its proper divisors (97219659).

213444981 is a wasteful number, since it uses less digits than its factorization.

213444981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 181176 (or 181173 counting only the distinct ones).

The product of its digits is 27648, while the sum is 36.

The square root of 213444981 is about 14609.7563634716. The cubic root of 213444981 is about 597.6248518587.

The spelling of 213444981 in words is "two hundred thirteen million, four hundred forty-four thousand, nine hundred eighty-one".