1231221401 has 2 divisors, whose sum is σ = 1231221402. Its totient is φ = 1231221400.

The previous prime is 1231221391. The next prime is 1231221421. The reversal of 1231221401 is 1041221321.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1216963225 + 14258176 = 34885^2 + 3776^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1231221401 is a prime.

It is a super-2 number, since 2×1231221401² = 3031812276560805602, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 1231221401.

It is not a weakly prime, because it can be changed into another prime (1231221421) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 615610700 + 615610701.

It is an arithmetic number, because the mean of its divisors is an integer number (615610701).

Almost surely, 2^1231221401 is an apocalyptic number.

It is an amenable number.

1231221401 is a deficient number, since it is larger than the sum of its proper divisors (1).

1231221401 is an equidigital number, since it uses as much as digits as its factorization.

1231221401 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 96, while the sum is 17.

The square root of 1231221401 is about 35088.7645978025. The cubic root of 1231221401 is about 1071.7958026195.

Adding to 1231221401 its reverse (1041221321), we get a palindrome (2272442722).

The spelling of 1231221401 in words is "one billion, two hundred thirty-one million, two hundred twenty-one thousand, four hundred one".