1211340021 has 4 divisors (see below), whose sum is σ = 1615120032. Its totient is φ = 807560012.

The previous prime is 1211340001. The next prime is 1211340023. The reversal of 1211340021 is 1200431121.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1211340021 - 2¹¹ = 1211337973 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1211340023) 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, 201890001 + ... + 201890006.

It is an arithmetic number, because the mean of its divisors is an integer number (403780008).

Almost surely, 2^1211340021 is an apocalyptic number.

It is an amenable number.

1211340021 is a deficient number, since it is larger than the sum of its proper divisors (403780011).

1211340021 is an equidigital number, since it uses as much as digits as its factorization.

1211340021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 403780010.

The product of its (nonzero) digits is 48, while the sum is 15.

The square root of 1211340021 is about 34804.3103796067. The cubic root of 1211340021 is about 1065.9954606168.

Adding to 1211340021 its reverse (1200431121), we get a palindrome (2411771142).

The spelling of 1211340021 in words is "one billion, two hundred eleven million, three hundred forty thousand, twenty-one".