239180661721 has 3 divisors (see below), whose sum is σ = 239181150783. Its totient is φ = 239180172660.

The previous prime is 239180661697. The next prime is 239180661763. The reversal of 239180661721 is 127166081932.

The square root of 239180661721 is 489061.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in only one way, i.e., 978121 + 239179683600 = 989^2 + 489060^2 .

It is not a de Polignac number, because 239180661721 - 2²³ = 239172273113 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (239180661791) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 244531 + ... + 733591.

It is an arithmetic number, because the mean of its divisors is an integer number (79727050261).

Almost surely, 2^239180661721 is an apocalyptic number.

239180661721 is the 489061-st square number.

239180661721 is the 282360-th hex number and also the 244531-st centered octagonal number.

It is an amenable number.

239180661721 is a deficient number, since it is larger than the sum of its proper divisors (489062).

239180661721 is an frugal number, since it uses more digits than its factorization.

239180661721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 978122 (or 489061 counting only the distinct ones).

The product of its (nonzero) digits is 217728, while the sum is 46.

The spelling of 239180661721 in words is "two hundred thirty-nine billion, one hundred eighty million, six hundred sixty-one thousand, seven hundred twenty-one".