391721467469 has 2 divisors, whose sum is σ = 391721467470. Its totient is φ = 391721467468.

The previous prime is 391721467421. The next prime is 391721467537. The reversal of 391721467469 is 964764127193.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 332386840900 + 59334626569 = 576530^2 + 243587^2 .

It is a cyclic number.

It is not a de Polignac number, because 391721467469 - 2¹⁶ = 391721401933 is a prime.

It is a super-2 number, since 2×391721467469² (a number of 24 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (391721467409) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 195860733734 + 195860733735.

It is an arithmetic number, because the mean of its divisors is an integer number (195860733735).

Almost surely, 2^391721467469 is an apocalyptic number.

It is an amenable number.

391721467469 is a deficient number, since it is larger than the sum of its proper divisors (1).

391721467469 is an equidigital number, since it uses as much as digits as its factorization.

391721467469 is an evil number, because the sum of its binary digits is even.

The product of its digits is 13716864, while the sum is 59.

The spelling of 391721467469 in words is "three hundred ninety-one billion, seven hundred twenty-one million, four hundred sixty-seven thousand, four hundred sixty-nine".