213504021 has 6 divisors (see below), whose sum is σ = 308394710. Its totient is φ = 142336008.

The previous prime is 213504017. The next prime is 213504041. The reversal of 213504021 is 120405312.

213504021 is a `hidden beast` number, since 213 + 50 + 402 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 124880625 + 88623396 = 11175^2 + 9414^2 .

It is not a de Polignac number, because 213504021 - 2² = 213504017 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 213503985 and 213504003.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (213504041) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 11861326 + ... + 11861343.

Almost surely, 2^213504021 is an apocalyptic number.

It is an amenable number.

213504021 is a deficient number, since it is larger than the sum of its proper divisors (94890689).

213504021 is a wasteful number, since it uses less digits than its factorization.

213504021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23722675 (or 23722672 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

The square root of 213504021 is about 14611.7767913420. The cubic root of 213504021 is about 597.6799488339.

Adding to 213504021 its reverse (120405312), we get a palindrome (333909333).

The spelling of 213504021 in words is "two hundred thirteen million, five hundred four thousand, twenty-one".