1221151 has 4 divisors (see below), whose sum is σ = 1225000. Its totient is φ = 1217304.

The previous prime is 1221131. The next prime is 1221163. The reversal of 1221151 is 1511221.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1511221 = 509 ⋅2969.

It is a cyclic number.

It is not a de Polignac number, because 1221151 - 2⁵ = 1221119 is a prime.

It is a Duffinian number.

1221151 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221131) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1401 + ... + 2098.

It is an arithmetic number, because the mean of its divisors is an integer number (306250).

2^1221151 is an apocalyptic number.

1221151 is a deficient number, since it is larger than the sum of its proper divisors (3849).

1221151 is an equidigital number, since it uses as much as digits as its factorization.

1221151 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3848.

The product of its digits is 20, while the sum is 13.

The square root of 1221151 is about 1105.0570121039. The cubic root of 1221151 is about 106.8865656692.

Adding to 1221151 its reverse (1511221), we get a palindrome (2732372).

The spelling of 1221151 in words is "one million, two hundred twenty-one thousand, one hundred fifty-one".