391799009421 has 16 divisors (see below), whose sum is σ = 581463110400. Its totient is φ = 260740279584.

The previous prime is 391799009383. The next prime is 391799009491. The reversal of 391799009421 is 124900997193.

It is a happy number.

It is not a de Polignac number, because 391799009421 - 2¹⁰ = 391799008397 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (391799009491) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 12736021 + ... + 12766746.

It is an arithmetic number, because the mean of its divisors is an integer number (36341444400).

Almost surely, 2^391799009421 is an apocalyptic number.

It is an amenable number.

391799009421 is a deficient number, since it is larger than the sum of its proper divisors (189664100979).

391799009421 is a wasteful number, since it uses less digits than its factorization.

391799009421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25503345 (or 25503339 counting only the distinct ones).

The product of its (nonzero) digits is 1102248, while the sum is 54.

The spelling of 391799009421 in words is "three hundred ninety-one billion, seven hundred ninety-nine million, nine thousand, four hundred twenty-one".