20621213 has 4 divisors (see below), whose sum is σ = 21706560. Its totient is φ = 19535868.

The previous prime is 20621191. The next prime is 20621239. The reversal of 20621213 is 31212602.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20621213 is a prime.

It is a super-3 number, since 3×20621213³ (a number of 23 digits) contains 333 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20621191 and 20621200.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20621243) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 542645 + ... + 542682.

It is an arithmetic number, because the mean of its divisors is an integer number (5426640).

Almost surely, 2^20621213 is an apocalyptic number.

It is an amenable number.

20621213 is a deficient number, since it is larger than the sum of its proper divisors (1085347).

20621213 is a wasteful number, since it uses less digits than its factorization.

20621213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1085346.

The product of its (nonzero) digits is 144, while the sum is 17.

The square root of 20621213 is about 4541.0585770280. The cubic root of 20621213 is about 274.2235419781.

Adding to 20621213 its reverse (31212602), we get a palindrome (51833815).

The spelling of 20621213 in words is "twenty million, six hundred twenty-one thousand, two hundred thirteen".