1211220101 has 16 divisors (see below), whose sum is σ = 1495853184. Its totient is φ = 955036224.

The previous prime is 1211220091. The next prime is 1211220107. The reversal of 1211220101 is 1010221121.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1211220101 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1211220107) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3950 + ... + 49376.

It is an arithmetic number, because the mean of its divisors is an integer number (93490824).

Almost surely, 2^1211220101 is an apocalyptic number.

It is an amenable number.

1211220101 is a deficient number, since it is larger than the sum of its proper divisors (284633083).

1211220101 is a wasteful number, since it uses less digits than its factorization.

1211220101 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45740.

The product of its (nonzero) digits is 8, while the sum is 11.

The square root of 1211220101 is about 34802.5875618466. The cubic root of 1211220101 is about 1065.9602823866.

Adding to 1211220101 its reverse (1010221121), we get a palindrome (2221441222).

The spelling of 1211220101 in words is "one billion, two hundred eleven million, two hundred twenty thousand, one hundred one".