221786994137 has 4 divisors (see below), whose sum is σ = 221788154496. Its totient is φ = 221785833780.

The previous prime is 221786994131. The next prime is 221786994179. The reversal of 221786994137 is 731499687122.

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 a de Polignac number, because none of the positive numbers 2^k-221786994137 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (221786994131) 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, 218189 + ... + 700842.

It is an arithmetic number, because the mean of its divisors is an integer number (55447038624).

Almost surely, 2^221786994137 is an apocalyptic number.

It is an amenable number.

221786994137 is a deficient number, since it is larger than the sum of its proper divisors (1160359).

221786994137 is an equidigital number, since it uses as much as digits as its factorization.

221786994137 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1160358.

The product of its digits is 9144576, while the sum is 59.

The spelling of 221786994137 in words is "two hundred twenty-one billion, seven hundred eighty-six million, nine hundred ninety-four thousand, one hundred thirty-seven".