1211278101 has 48 divisors (see below), whose sum is σ = 1969178688. Its totient is φ = 654451200.

The previous prime is 1211278099. The next prime is 1211278111. The reversal of 1211278101 is 1018721121.

It is not a de Polignac number, because 1211278101 - 2¹ = 1211278099 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1211278111) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 199531 + ... + 205511.

It is an arithmetic number, because the mean of its divisors is an integer number (41024556).

Almost surely, 2^1211278101 is an apocalyptic number.

1211278101 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1211278101 is a deficient number, since it is larger than the sum of its proper divisors (757900587).

1211278101 is a wasteful number, since it uses less digits than its factorization.

1211278101 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6050 (or 6031 counting only the distinct ones).

The product of its (nonzero) digits is 224, while the sum is 24.

The square root of 1211278101 is about 34803.4208232467. The cubic root of 1211278101 is about 1065.9772968306.

Adding to 1211278101 its reverse (1018721121), we get a palindrome (2229999222).

The spelling of 1211278101 in words is "one billion, two hundred eleven million, two hundred seventy-eight thousand, one hundred one".