398831367661 has 4 divisors (see below), whose sum is σ = 409610593852. Its totient is φ = 388052141472.

The previous prime is 398831367643. The next prime is 398831367691. The reversal of 398831367661 is 166763138893.

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

It can be written as a sum of positive squares in 2 ways, for example, as 347134250761 + 51697116900 = 589181^2 + 227370^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-398831367661 is a prime.

It is a super-2 number, since 2×398831367661² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 398831367661.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (398831367691) 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, 5389613040 + ... + 5389613113.

It is an arithmetic number, because the mean of its divisors is an integer number (102402648463).

Almost surely, 2^398831367661 is an apocalyptic number.

It is an amenable number.

398831367661 is a deficient number, since it is larger than the sum of its proper divisors (10779226191).

398831367661 is a wasteful number, since it uses less digits than its factorization.

398831367661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10779226190.

The product of its digits is 23514624, while the sum is 61.

The spelling of 398831367661 in words is "three hundred ninety-eight billion, eight hundred thirty-one million, three hundred sixty-seven thousand, six hundred sixty-one".