2139218177781 has 4 divisors (see below), whose sum is σ = 2852290903712. Its totient is φ = 1426145451852.

The previous prime is 2139218177777. The next prime is 2139218177791. The reversal of 2139218177781 is 1877718129312.

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 not a de Polignac number, because 2139218177781 - 2² = 2139218177777 is a prime.

It is a super-2 number, since 2×2139218177781² (a number of 25 digits) 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 (2139218177741) 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, 356536362961 + ... + 356536362966.

It is an arithmetic number, because the mean of its divisors is an integer number (713072725928).

Almost surely, 2^{2139218177781} is an apocalyptic number.

It is an amenable number.

2139218177781 is a deficient number, since it is larger than the sum of its proper divisors (713072725931).

2139218177781 is an equidigital number, since it uses as much as digits as its factorization.

2139218177781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 713072725930.

The product of its digits is 2370816, while the sum is 57.

The spelling of 2139218177781 in words is "two trillion, one hundred thirty-nine billion, two hundred eighteen million, one hundred seventy-seven thousand, seven hundred eighty-one".