1001218021 has 4 divisors (see below), whose sum is σ = 1002534444. Its totient is φ = 999901600.

The previous prime is 1001218013. The next prime is 1001218027. The reversal of 1001218021 is 1208121001.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 34692100 + 966525921 = 5890^2 + 31089^2 .

It is a cyclic number.

It is not a de Polignac number, because 1001218021 - 2³ = 1001218013 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1001217986 and 1001218004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1001218027) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 657070 + ... + 658591.

It is an arithmetic number, because the mean of its divisors is an integer number (250633611).

Almost surely, 2^1001218021 is an apocalyptic number.

It is an amenable number.

1001218021 is a deficient number, since it is larger than the sum of its proper divisors (1316423).

1001218021 is an equidigital number, since it uses as much as digits as its factorization.

1001218021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1316422.

The product of its (nonzero) digits is 32, while the sum is 16.

The square root of 1001218021 is about 31642.0293438964. The cubic root of 1001218021 is about 1000.4058422698.

Adding to 1001218021 its reverse (1208121001), we get a palindrome (2209339022).

It can be divided in two parts, 100 and 1218021, that added together give a palindrome (1218121).

The spelling of 1001218021 in words is "one billion, one million, two hundred eighteen thousand, twenty-one".