1211720151 has 8 divisors (see below), whose sum is σ = 1638382464. Its totient is φ = 796435640.

The previous prime is 1211720149. The next prime is 1211720161. The reversal of 1211720151 is 1510271121.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1211720151 - 2¹ = 1211720149 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1211720161) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2844201 + ... + 2844626.

It is an arithmetic number, because the mean of its divisors is an integer number (204797808).

Almost surely, 2^1211720151 is an apocalyptic number.

1211720151 is a deficient number, since it is larger than the sum of its proper divisors (426662313).

1211720151 is an equidigital number, since it uses as much as digits as its factorization.

1211720151 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5688901.

The product of its (nonzero) digits is 140, while the sum is 21.

The square root of 1211720151 is about 34809.7709127768. The cubic root of 1211720151 is about 1066.1069554539.

Adding to 1211720151 its reverse (1510271121), we get a palindrome (2721991272).

The spelling of 1211720151 in words is "one billion, two hundred eleven million, seven hundred twenty thousand, one hundred fifty-one".