20010021 has 8 divisors (see below), whose sum is σ = 28084320. Its totient is φ = 12637872.

The previous prime is 20010017. The next prime is 20010041. The reversal of 20010021 is 12001002.

It is a happy number.

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

It is not a de Polignac number, because 20010021 - 2² = 20010017 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20009991 and 20010009.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20010041) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 175470 + ... + 175583.

It is an arithmetic number, because the mean of its divisors is an integer number (3510540).

Almost surely, 2^20010021 is an apocalyptic number.

It is an amenable number.

20010021 is a deficient number, since it is larger than the sum of its proper divisors (8074299).

20010021 is a wasteful number, since it uses less digits than its factorization.

20010021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 351075.

The product of its (nonzero) digits is 4, while the sum is 6.

The square root of 20010021 is about 4473.2561965530. The cubic root of 20010021 is about 271.4870893881.

Adding to 20010021 its reverse (12001002), we get a palindrome (32011023).

The spelling of 20010021 in words is "twenty million, ten thousand, twenty-one".