20213445 has 32 divisors (see below), whose sum is σ = 37140480. Its totient is φ = 9195840.

The previous prime is 20213443. The next prime is 20213461. The reversal of 20213445 is 54431202.

It is not a de Polignac number, because 20213445 - 2¹ = 20213443 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20213443) 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 31 ways as a sum of consecutive naturals, for example, 32346 + ... + 32964.

It is an arithmetic number, because the mean of its divisors is an integer number (1160640).

Almost surely, 2^20213445 is an apocalyptic number.

It is an amenable number.

20213445 is a deficient number, since it is larger than the sum of its proper divisors (16927035).

20213445 is a wasteful number, since it uses less digits than its factorization.

20213445 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 945.

The product of its (nonzero) digits is 960, while the sum is 21.

The square root of 20213445 is about 4495.9364986619. The cubic root of 20213445 is about 272.4039781764.

Adding to 20213445 its reverse (54431202), we get a palindrome (74644647).

The spelling of 20213445 in words is "twenty million, two hundred thirteen thousand, four hundred forty-five".