1211550001 has 4 divisors (see below), whose sum is σ = 1264226112. Its totient is φ = 1158873892.

The previous prime is 1211549987. The next prime is 1211550017. The reversal of 1211550001 is 1000551121.

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 1211550001 - 2⁷ = 1211549873 is a prime.

It is a super-3 number, since 3×1211550001³ (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 (1211550031) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 26338021 + ... + 26338066.

It is an arithmetic number, because the mean of its divisors is an integer number (316056528).

Almost surely, 2^1211550001 is an apocalyptic number.

It is an amenable number.

1211550001 is a deficient number, since it is larger than the sum of its proper divisors (52676111).

1211550001 is an equidigital number, since it uses as much as digits as its factorization.

1211550001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 52676110.

The product of its (nonzero) digits is 50, while the sum is 16.

The square root of 1211550001 is about 34807.3268292755. The cubic root of 1211550001 is about 1066.0570521299.

The spelling of 1211550001 in words is "one billion, two hundred eleven million, five hundred fifty thousand, one".