213610021 has 2 divisors, whose sum is σ = 213610022. Its totient is φ = 213610020.

The previous prime is 213609943. The next prime is 213610037. The reversal of 213610021 is 120016312.

It is an a-pointer prime, because the next prime (213610037) can be obtained adding 213610021 to its sum of digits (16).

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 212430625 + 1179396 = 14575^2 + 1086^2 .

It is a cyclic number.

It is not a de Polignac number, because 213610021 - 2¹⁷ = 213478949 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 213609977 and 213610004.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (213610081) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 106805010 + 106805011.

It is an arithmetic number, because the mean of its divisors is an integer number (106805011).

Almost surely, 2^213610021 is an apocalyptic number.

It is an amenable number.

213610021 is a deficient number, since it is larger than the sum of its proper divisors (1).

213610021 is an equidigital number, since it uses as much as digits as its factorization.

213610021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 72, while the sum is 16.

The square root of 213610021 is about 14615.4035524169. The cubic root of 213610021 is about 597.7788440718.

Adding to 213610021 its reverse (120016312), we get a palindrome (333626333).

The spelling of 213610021 in words is "two hundred thirteen million, six hundred ten thousand, twenty-one".