213125009 has 4 divisors (see below), whose sum is σ = 214680804. Its totient is φ = 211569216.

The previous prime is 213124999. The next prime is 213125021. The reversal of 213125009 is 900521312.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 152596609 + 60528400 = 12353^2 + 7780^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-213125009 is a prime.

It is a super-2 number, since 2×213125009² = 90844538922500162, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (213125309) 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, 777692 + ... + 777965.

It is an arithmetic number, because the mean of its divisors is an integer number (53670201).

Almost surely, 2^213125009 is an apocalyptic number.

It is an amenable number.

213125009 is a deficient number, since it is larger than the sum of its proper divisors (1555795).

213125009 is a wasteful number, since it uses less digits than its factorization.

213125009 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1555794.

The product of its (nonzero) digits is 540, while the sum is 23.

The square root of 213125009 is about 14598.8016289009. The cubic root of 213125009 is about 597.3260725181.

The spelling of 213125009 in words is "two hundred thirteen million, one hundred twenty-five thousand, nine".