213555021 has 16 divisors (see below), whose sum is σ = 287738880. Its totient is φ = 140877360.

The previous prime is 213554993. The next prime is 213555029. The reversal of 213555021 is 120555312.

It is a happy number.

It is not a de Polignac number, because 213555021 - 2⁵ = 213554989 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 213554982 and 213555000.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (213555029) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 205020 + ... + 206058.

It is an arithmetic number, because the mean of its divisors is an integer number (17983680).

Almost surely, 2^213555021 is an apocalyptic number.

It is an amenable number.

213555021 is a deficient number, since it is larger than the sum of its proper divisors (74183859).

213555021 is a wasteful number, since it uses less digits than its factorization.

213555021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1696.

The product of its (nonzero) digits is 1500, while the sum is 24.

The square root of 213555021 is about 14613.5218547755. The cubic root of 213555021 is about 597.7275345898.

The spelling of 213555021 in words is "two hundred thirteen million, five hundred fifty-five thousand, twenty-one".