1211005421 has 8 divisors (see below), whose sum is σ = 1323604224. Its totient is φ = 1103002560.

The previous prime is 1211005417. The next prime is 1211005423. The reversal of 1211005421 is 1245001121.

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

It is a cyclic number.

It is not a de Polignac number, because 1211005421 - 2² = 1211005417 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (17).

It is a self number, because there is not a number n which added to its sum of digits gives 1211005421.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1211005423) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1148435 + ... + 1149488.

It is an arithmetic number, because the mean of its divisors is an integer number (165450528).

Almost surely, 2^1211005421 is an apocalyptic number.

It is an amenable number.

1211005421 is a deficient number, since it is larger than the sum of its proper divisors (112598803).

1211005421 is a wasteful number, since it uses less digits than its factorization.

1211005421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2297971.

The product of its (nonzero) digits is 80, while the sum is 17.

The square root of 1211005421 is about 34799.5031717408. The cubic root of 1211005421 is about 1065.8973007495.

Adding to 1211005421 its reverse (1245001121), we get a palindrome (2456006542).

The spelling of 1211005421 in words is "one billion, two hundred eleven million, five thousand, four hundred twenty-one".