1131211391 has 4 divisors (see below), whose sum is σ = 1131299400. Its totient is φ = 1131123384.

The previous prime is 1131211373. The next prime is 1131211441. The reversal of 1131211391 is 1931121311.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1131211391 is a prime.

It is a super-2 number, since 2×1131211391² = 2559278422256309762, 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 (1131211891) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 20561 + ... + 51818.

It is an arithmetic number, because the mean of its divisors is an integer number (282824850).

Almost surely, 2^1131211391 is an apocalyptic number.

1131211391 is a deficient number, since it is larger than the sum of its proper divisors (88009).

1131211391 is an equidigital number, since it uses as much as digits as its factorization.

1131211391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 88008.

The product of its digits is 162, while the sum is 23.

The square root of 1131211391 is about 33633.4861559131. The cubic root of 1131211391 is about 1041.9525053169.

The spelling of 1131211391 in words is "one billion, one hundred thirty-one million, two hundred eleven thousand, three hundred ninety-one".