1181865138421 has 4 divisors (see below), whose sum is σ = 1289307423744. Its totient is φ = 1074422853100.

The previous prime is 1181865138409. The next prime is 1181865138521. The reversal of 1181865138421 is 1248315681811.

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.

It is a cyclic number.

It is not a de Polignac number, because 1181865138421 - 2²³ = 1181856749813 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1181865138521) 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, 53721142645 + ... + 53721142666.

It is an arithmetic number, because the mean of its divisors is an integer number (322326855936).

Almost surely, 2^{1181865138421} is an apocalyptic number.

1181865138421 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1181865138421 is a deficient number, since it is larger than the sum of its proper divisors (107442285323).

1181865138421 is a wasteful number, since it uses less digits than its factorization.

1181865138421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 107442285322.

The product of its digits is 368640, while the sum is 49.

The spelling of 1181865138421 in words is "one trillion, one hundred eighty-one billion, eight hundred sixty-five million, one hundred thirty-eight thousand, four hundred twenty-one".