1211400121 has 4 divisors (see below), whose sum is σ = 1212427044. Its totient is φ = 1210373200.

The previous prime is 1211400103. The next prime is 1211400139. The reversal of 1211400121 is 1210041121.

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

It is an interprime number because it is at equal distance from previous prime (1211400103) and next prime (1211400139).

It can be written as a sum of positive squares in 2 ways, for example, as 481319721 + 730080400 = 21939^2 + 27020^2 .

It is a cyclic number.

It is not a de Polignac number, because 1211400121 - 2²⁵ = 1177845689 is a prime.

It is a super-3 number, since 3×1211400121³ (a number of 28 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1211400191) 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 3 ways as a sum of consecutive naturals, for example, 511690 + ... + 514051.

It is an arithmetic number, because the mean of its divisors is an integer number (303106761).

Almost surely, 2^1211400121 is an apocalyptic number.

It is an amenable number.

1211400121 is a deficient number, since it is larger than the sum of its proper divisors (1026923).

1211400121 is a wasteful number, since it uses less digits than its factorization.

1211400121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1026922.

The product of its (nonzero) digits is 16, while the sum is 13.

The square root of 1211400121 is about 34805.1737677030. The cubic root of 1211400121 is about 1066.0130899272.

Adding to 1211400121 its reverse (1210041121), we get a palindrome (2421441242).

The spelling of 1211400121 in words is "one billion, two hundred eleven million, four hundred thousand, one hundred twenty-one".