1020000021 has 8 divisors (see below), whose sum is σ = 1419130560. Its totient is φ = 650434752.

The previous prime is 1020000013. The next prime is 1020000061. The reversal of 1020000021 is 1200000201.

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 1020000021 - 2³ = 1020000013 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1019999964 and 1020000009.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1020000011) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7391236 + ... + 7391373.

It is an arithmetic number, because the mean of its divisors is an integer number (177391320).

Almost surely, 2^1020000021 is an apocalyptic number.

It is an amenable number.

1020000021 is a deficient number, since it is larger than the sum of its proper divisors (399130539).

1020000021 is a wasteful number, since it uses less digits than its factorization.

1020000021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14782635.

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

The square root of 1020000021 is about 31937.4391741104. The cubic root of 1020000021 is about 1006.6227164683.

Adding to 1020000021 its reverse (1200000201), we get a palindrome (2220000222).

The spelling of 1020000021 in words is "one billion, twenty million, twenty-one", and thus it is an aban number and an uban number.