1211501161 has 16 divisors (see below), whose sum is σ = 1386987840. Its totient is φ = 1048939200.

The previous prime is 1211501143. The next prime is 1211501171. The reversal of 1211501161 is 1611051121.

It is a cyclic number.

It is not a de Polignac number, because 1211501161 - 2⁷ = 1211501033 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (19).

It is not an unprimeable number, because it can be changed into a prime (1211501171) 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, 666 + ... + 49228.

It is an arithmetic number, because the mean of its divisors is an integer number (86686740).

Almost surely, 2^1211501161 is an apocalyptic number.

It is an amenable number.

1211501161 is a deficient number, since it is larger than the sum of its proper divisors (175486679).

1211501161 is a wasteful number, since it uses less digits than its factorization.

1211501161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 48696.

The product of its (nonzero) digits is 60, while the sum is 19.

The square root of 1211501161 is about 34806.6252457776. The cubic root of 1211501161 is about 1066.0427269745.

Adding to 1211501161 its reverse (1611051121), we get a palindrome (2822552282).

The spelling of 1211501161 in words is "one billion, two hundred eleven million, five hundred one thousand, one hundred sixty-one".