1231222151 has 4 divisors (see below), whose sum is σ = 1240209312. Its totient is φ = 1222234992.

The previous prime is 1231222129. The next prime is 1231222159. The reversal of 1231222151 is 1512221321.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1512221321 = 13 ⋅116324717.

It is a cyclic number.

It is not a de Polignac number, because 1231222151 - 2¹⁸ = 1230960007 is a prime.

It is a super-2 number, since 2×1231222151² = 3031815970226133602, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1231222159) 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, 4493375 + ... + 4493648.

It is an arithmetic number, because the mean of its divisors is an integer number (310052328).

Almost surely, 2^1231222151 is an apocalyptic number.

1231222151 is a deficient number, since it is larger than the sum of its proper divisors (8987161).

1231222151 is an equidigital number, since it uses as much as digits as its factorization.

1231222151 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8987160.

The product of its digits is 240, while the sum is 20.

The square root of 1231222151 is about 35088.7752849825. The cubic root of 1231222151 is about 1071.7960202480.

Adding to 1231222151 its reverse (1512221321), we get a palindrome (2743443472).

The spelling of 1231222151 in words is "one billion, two hundred thirty-one million, two hundred twenty-two thousand, one hundred fifty-one".