391789616761 has 15 divisors (see below), whose sum is σ = 402449950661. Its totient is φ = 381409802988.

The previous prime is 391789616747. The next prime is 391789616789. The reversal of 391789616761 is 167616987193.

The square root of 391789616761 is 625931.

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

It is not a de Polignac number, because 391789616761 - 2⁷ = 391789616633 is a prime.

It is a super-4 number, since 4×391789616761⁴ (a number of 47 digits) contains 4444 as substring. Note that it is a super-d number also for d = 3, 2.

It is a Duffinian number.

Its product of digits (20575296) is a multiple of the sum of its prime divisors (162).

It is a junction number, because it is equal to n+sod(n) for n = 391789616693 and 391789616702.

It is not an unprimeable number, because it can be changed into a prime (391789616861) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 14 ways as a sum of consecutive naturals, for example, 3803782636 + ... + 3803782738.

Almost surely, 2^391789616761 is an apocalyptic number.

391789616761 is the 625931-st square number.

391789616761 is the 312966-th centered octagonal number.

It is an amenable number.

391789616761 is a deficient number, since it is larger than the sum of its proper divisors (10660333900).

391789616761 is an frugal number, since it uses more digits than its factorization.

391789616761 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 530 (or 162 counting only the distinct ones).

The product of its digits is 20575296, while the sum is 64.

Multiplying 391789616761 by its sum of digits (64), we get a square (25074535472704 = 5007448²).

The spelling of 391789616761 in words is "three hundred ninety-one billion, seven hundred eighty-nine million, six hundred sixteen thousand, seven hundred sixty-one".