1181828381 has 4 divisors (see below), whose sum is σ = 1181914272. Its totient is φ = 1181742492.

The previous prime is 1181828377. The next prime is 1181828497. The reversal of 1181828381 is 1838281811.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 1181828381 - 2² = 1181828377 is a prime.

It is a super-2 number, since 2×1181828381² = 2793436644274162322, 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 (1181828311) 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, 17135 + ... + 51548.

It is an arithmetic number, because the mean of its divisors is an integer number (295478568).

Almost surely, 2^1181828381 is an apocalyptic number.

It is an amenable number.

1181828381 is a deficient number, since it is larger than the sum of its proper divisors (85891).

1181828381 is an equidigital number, since it uses as much as digits as its factorization.

1181828381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 85890.

The product of its digits is 24576, while the sum is 41.

The square root of 1181828381 is about 34377.7308878873. The cubic root of 1181828381 is about 1057.2673117617.

The spelling of 1181828381 in words is "one billion, one hundred eighty-one million, eight hundred twenty-eight thousand, three hundred eighty-one".