2012100021 has 12 divisors (see below), whose sum is σ = 3014010272. Its totient is φ = 1341399852.

The previous prime is 2012099983. The next prime is 2012100037. The reversal of 2012100021 is 1200012102.

It is not a de Polignac number, because 2012100021 - 2⁷ = 2012099893 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 2012099976 and 2012100012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2012100061) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 4139881 + ... + 4140366.

Almost surely, 2^2012100021 is an apocalyptic number.

It is an amenable number.

2012100021 is a deficient number, since it is larger than the sum of its proper divisors (1001910251).

2012100021 is an frugal number, since it uses more digits than its factorization.

2012100021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8280262 (or 8280250 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 9.

The square root of 2012100021 is about 44856.4378991467. The cubic root of 2012100021 is about 1262.4567881952.

Adding to 2012100021 its reverse (1200012102), we get a palindrome (3212112123).

The spelling of 2012100021 in words is "two billion, twelve million, one hundred thousand, twenty-one".