213432981 has 4 divisors (see below), whose sum is σ = 284577312. Its totient is φ = 142288652.

The previous prime is 213432959. The next prime is 213432991. The reversal of 213432981 is 189234312.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 213432981 - 2⁵ = 213432949 is a prime.

It is a super-2 number, since 2×213432981² = 91107274757092722, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (213432911) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 35572161 + ... + 35572166.

It is an arithmetic number, because the mean of its divisors is an integer number (71144328).

Almost surely, 2^213432981 is an apocalyptic number.

It is an amenable number.

213432981 is a deficient number, since it is larger than the sum of its proper divisors (71144331).

213432981 is an equidigital number, since it uses as much as digits as its factorization.

213432981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 71144330.

The product of its digits is 10368, while the sum is 33.

The square root of 213432981 is about 14609.3456732326. The cubic root of 213432981 is about 597.6136520441.

The spelling of 213432981 in words is "two hundred thirteen million, four hundred thirty-two thousand, nine hundred eighty-one".