1211221431 has 20 divisors (see below), whose sum is σ = 2067835792. Its totient is φ = 692126208.

The previous prime is 1211221409. The next prime is 1211221433. The reversal of 1211221431 is 1341221121.

1211221431 is a `hidden beast` number, since 1 + 2 + 11 + 221 + 431 = 666.

It is not a de Polignac number, because 1211221431 - 2¹³ = 1211213239 is a prime.

It is a super-2 number, since 2×1211221431² = 2934114709827375522, 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 (1211221433) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 1067530 + ... + 1068663.

Almost surely, 2^1211221431 is an apocalyptic number.

1211221431 is a deficient number, since it is larger than the sum of its proper divisors (856614361).

1211221431 is an equidigital number, since it uses as much as digits as its factorization.

1211221431 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2136212 (or 2136203 counting only the distinct ones).

The product of its digits is 96, while the sum is 18.

The square root of 1211221431 is about 34802.6066696160. The cubic root of 1211221431 is about 1065.9606725515.

Adding to 1211221431 its reverse (1341221121), we get a palindrome (2552442552).

The spelling of 1211221431 in words is "one billion, two hundred eleven million, two hundred twenty-one thousand, four hundred thirty-one".