20155213 has 4 divisors (see below), whose sum is σ = 21705628. Its totient is φ = 18604800.

The previous prime is 20155169. The next prime is 20155249. The reversal of 20155213 is 31255102.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 9998244 + 10156969 = 3162^2 + 3187^2 .

It is a cyclic number.

It is not a de Polignac number, because 20155213 - 2¹³ = 20147021 is a prime.

It is a super-2 number, since 2×20155213² = 812465222150738, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20155283) 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 3 ways as a sum of consecutive naturals, for example, 775188 + ... + 775213.

It is an arithmetic number, because the mean of its divisors is an integer number (5426407).

Almost surely, 2^20155213 is an apocalyptic number.

It is an amenable number.

20155213 is a deficient number, since it is larger than the sum of its proper divisors (1550415).

20155213 is a wasteful number, since it uses less digits than its factorization.

20155213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1550414.

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

The square root of 20155213 is about 4489.4557576615. The cubic root of 20155213 is about 272.1421411412.

The spelling of 20155213 in words is "twenty million, one hundred fifty-five thousand, two hundred thirteen".