20621217 has 8 divisors (see below), whose sum is σ = 27539200. Its totient is φ = 13725360.

The previous prime is 20621191. The next prime is 20621239. The reversal of 20621217 is 71212602.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 20621217 - 2⁷ = 20621089 is a prime.

It is a super-2 number, since 2×20621217² = 850469181122178, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20621193 and 20621202.

It is not an unprimeable number, because it can be changed into a prime (20621287) 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 7 ways as a sum of consecutive naturals, for example, 3217 + ... + 7182.

It is an arithmetic number, because the mean of its divisors is an integer number (3442400).

Almost surely, 2^20621217 is an apocalyptic number.

It is an amenable number.

20621217 is a deficient number, since it is larger than the sum of its proper divisors (6917983).

20621217 is a wasteful number, since it uses less digits than its factorization.

20621217 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11063.

The product of its (nonzero) digits is 336, while the sum is 21.

The square root of 20621217 is about 4541.0590174540. The cubic root of 20621217 is about 274.2235597090.

Adding to 20621217 its reverse (71212602), we get a palindrome (91833819).

The spelling of 20621217 in words is "twenty million, six hundred twenty-one thousand, two hundred seventeen".