1210100021 has 8 divisors (see below), whose sum is σ = 1304015160. Its totient is φ = 1116303552.

The previous prime is 1210099993. The next prime is 1210100027. The reversal of 1210100021 is 1200010121.

It can be written as a sum of positive squares in 4 ways, for example, as 34225 + 1210065796 = 185^2 + 34786^2 .

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

It is not a de Polignac number, because 1210100021 - 2¹⁰ = 1210098997 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1210099981 and 1210100008.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1210100027) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7886 + ... + 49823.

It is an arithmetic number, because the mean of its divisors is an integer number (163001895).

Almost surely, 2^1210100021 is an apocalyptic number.

It is an amenable number.

1210100021 is a deficient number, since it is larger than the sum of its proper divisors (93915139).

1210100021 is a wasteful number, since it uses less digits than its factorization.

1210100021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 59335.

The product of its (nonzero) digits is 4, while the sum is 8.

The square root of 1210100021 is about 34786.4919329328. The cubic root of 1210100021 is about 1065.6315975558.

Adding to 1210100021 its reverse (1200010121), we get a palindrome (2410110142).

The spelling of 1210100021 in words is "one billion, two hundred ten million, one hundred thousand, twenty-one".