221718138770731 has 4 divisors (see below), whose sum is σ = 221718234856464. Its totient is φ = 221718042685000.

The previous prime is 221718138770729. The next prime is 221718138770749. The reversal of 221718138770731 is 137077831817122.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 221718138770731 - 2¹ = 221718138770729 is a prime.

It is a super-2 number, since 2×221718138770731² (a number of 29 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (221718138770761) 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, 44494240 + ... + 49225741.

It is an arithmetic number, because the mean of its divisors is an integer number (55429558714116).

Almost surely, 2^{221718138770731} is an apocalyptic number.

221718138770731 is a deficient number, since it is larger than the sum of its proper divisors (96085733).

221718138770731 is an equidigital number, since it uses as much as digits as its factorization.

221718138770731 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 96085732.

The product of its (nonzero) digits is 5531904, while the sum is 58.

The spelling of 221718138770731 in words is "two hundred twenty-one trillion, seven hundred eighteen billion, one hundred thirty-eight million, seven hundred seventy thousand, seven hundred thirty-one".