398516781 has 16 divisors (see below), whose sum is σ = 579128256. Its totient is φ = 242284416.

The previous prime is 398516777. The next prime is 398516801. The reversal of 398516781 is 187615893.

It is not a de Polignac number, because 398516781 - 2² = 398516777 is a prime.

It is a super-4 number, since 4×398516781⁴ (a number of 36 digits) contains 4444 as substring. Note that it is a super-d number also for d = 2.

It is a self number, because there is not a number n which added to its sum of digits gives 398516781.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (398516081) 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, 58320 + ... + 64793.

It is an arithmetic number, because the mean of its divisors is an integer number (36195516).

Almost surely, 2^398516781 is an apocalyptic number.

It is an amenable number.

398516781 is a deficient number, since it is larger than the sum of its proper divisors (180611475).

398516781 is a wasteful number, since it uses less digits than its factorization.

398516781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 123212.

The product of its digits is 362880, while the sum is 48.

The square root of 398516781 is about 19962.8850870810. The cubic root of 398516781 is about 735.8944675060.

The spelling of 398516781 in words is "three hundred ninety-eight million, five hundred sixteen thousand, seven hundred eighty-one".