20621017 has 6 divisors (see below), whose sum is σ = 21905678. Its totient is φ = 19407744.

The previous prime is 20621009. The next prime is 20621063. The reversal of 20621017 is 71012602.

It can be written as a sum of positive squares in 3 ways, for example, as 15531481 + 5089536 = 3941^2 + 2256^2 .

It is not a de Polignac number, because 20621017 - 2³ = 20621009 is a prime.

It is a super-2 number, since 2×20621017² = 850452684228578, 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 = 20620985 and 20621003.

It is not an unprimeable number, because it can be changed into a prime (20621077) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 35388 + ... + 35965.

Almost surely, 2^20621017 is an apocalyptic number.

It is an amenable number.

20621017 is a deficient number, since it is larger than the sum of its proper divisors (1284661).

20621017 is an equidigital number, since it uses as much as digits as its factorization.

20621017 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 71387 (or 71370 counting only the distinct ones).

The product of its (nonzero) digits is 168, while the sum is 19.

The square root of 20621017 is about 4541.0369961056. The cubic root of 20621017 is about 274.2226731643. Note that the first 3 decimals are identical.

Adding to 20621017 its reverse (71012602), we get a palindrome (91633619).

The spelling of 20621017 in words is "twenty million, six hundred twenty-one thousand, seventeen".