213240021 has 8 divisors (see below), whose sum is σ = 299284320. Its totient is φ = 134677872.

The previous prime is 213240017. The next prime is 213240037. The reversal of 213240021 is 120042312.

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

It is not a de Polignac number, because 213240021 - 2² = 213240017 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (213240721) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1870470 + ... + 1870583.

It is an arithmetic number, because the mean of its divisors is an integer number (37410540).

Almost surely, 2^213240021 is an apocalyptic number.

It is an amenable number.

213240021 is a deficient number, since it is larger than the sum of its proper divisors (86044299).

213240021 is a wasteful number, since it uses less digits than its factorization.

213240021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3741075.

The product of its (nonzero) digits is 96, while the sum is 15.

The square root of 213240021 is about 14602.7401880606. The cubic root of 213240021 is about 597.4335013498.

Adding to 213240021 its reverse (120042312), we get a palindrome (333282333).

The spelling of 213240021 in words is "two hundred thirteen million, two hundred forty thousand, twenty-one".