20155321 has 2 divisors, whose sum is σ = 20155322. Its totient is φ = 20155320.

The previous prime is 20155307. The next prime is 20155327. The reversal of 20155321 is 12355102.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 10169721 + 9985600 = 3189^2 + 3160^2 .

It is a cyclic number.

It is not a de Polignac number, because 20155321 - 2¹⁹ = 19631033 is a prime.

It is a super-2 number, since 2×20155321² = 812473929226082, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (20155327) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10077660 + 10077661.

It is an arithmetic number, because the mean of its divisors is an integer number (10077661).

Almost surely, 2^20155321 is an apocalyptic number.

It is an amenable number.

20155321 is a deficient number, since it is larger than the sum of its proper divisors (1).

20155321 is an equidigital number, since it uses as much as digits as its factorization.

20155321 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 300, while the sum is 19.

The square root of 20155321 is about 4489.4677858294. The cubic root of 20155321 is about 272.1426272239.

The spelling of 20155321 in words is "twenty million, one hundred fifty-five thousand, three hundred twenty-one".