213121985 has 8 divisors (see below), whose sum is σ = 256473000. Its totient is φ = 170013184.

The previous prime is 213121973. The next prime is 213121991. The reversal of 213121985 is 589121312.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 8288641 + 204833344 = 2879^2 + 14312^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 213121985 - 2⁴ = 213121969 is a prime.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 58610 + ... + 62139.

It is an arithmetic number, because the mean of its divisors is an integer number (32059125).

Almost surely, 2^213121985 is an apocalyptic number.

It is an amenable number.

213121985 is a deficient number, since it is larger than the sum of its proper divisors (43351015).

213121985 is a wasteful number, since it uses less digits than its factorization.

213121985 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 121107.

The product of its digits is 4320, while the sum is 32.

The square root of 213121985 is about 14598.6980583886. The cubic root of 213121985 is about 597.3232473803.

The spelling of 213121985 in words is "two hundred thirteen million, one hundred twenty-one thousand, nine hundred eighty-five".