3520021 has 2 divisors, whose sum is σ = 3520022. Its totient is φ = 3520020.

The previous prime is 3520009. The next prime is 3520043. The reversal of 3520021 is 1200253.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 3010225 + 509796 = 1735^2 + 714^2 .

It is an emirp because it is prime and its reverse (1200253) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 3520021 - 2¹⁷ = 3388949 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 3519983 and 3520010.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (3520051) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1760010 + 1760011.

It is an arithmetic number, because the mean of its divisors is an integer number (1760011).

Almost surely, 2^3520021 is an apocalyptic number.

It is an amenable number.

3520021 is a deficient number, since it is larger than the sum of its proper divisors (1).

3520021 is an equidigital number, since it uses as much as digits as its factorization.

3520021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 60, while the sum is 13.

The square root of 3520021 is about 1876.1719004398. The cubic root of 3520021 is about 152.1184009374.

Adding to 3520021 its reverse (1200253), we get a palindrome (4720274).

The spelling of 3520021 in words is "three million, five hundred twenty thousand, twenty-one".