1221221131 has 8 divisors (see below), whose sum is σ = 1315432944. Its totient is φ = 1127048160.

The previous prime is 1221221119. The next prime is 1221221153. The reversal of 1221221131 is 1311221221.

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 1221221131 - 2⁷ = 1221221003 is a prime.

It is a super-2 number, since 2×1221221131² = 2982762101601838322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1221227131) 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, 114861 + ... + 125041.

It is an arithmetic number, because the mean of its divisors is an integer number (164429118).

Almost surely, 2^1221221131 is an apocalyptic number.

1221221131 is a deficient number, since it is larger than the sum of its proper divisors (94211813).

1221221131 is a wasteful number, since it uses less digits than its factorization.

1221221131 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19421.

The product of its digits is 48, while the sum is 16.

The square root of 1221221131 is about 34945.9744605870. The cubic root of 1221221131 is about 1068.8861180391.

Adding to 1221221131 its reverse (1311221221), we get a palindrome (2532442352).

It can be divided in two parts, 1221221 and 131, that multiplied together give a palindrome (159979951).

The spelling of 1221221131 in words is "one billion, two hundred twenty-one million, two hundred twenty-one thousand, one hundred thirty-one".