398704400021 has 8 divisors (see below), whose sum is σ = 400517165400. Its totient is φ = 396892258560.

The previous prime is 398704400011. The next prime is 398704400053. The reversal of 398704400021 is 120004407893.

It can be written as a sum of positive squares in 4 ways, for example, as 234172759396 + 164531640625 = 483914^2 + 405625^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-398704400021 is a prime.

It is a super-2 number, since 2×398704400021² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (398704400011) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1149761 + ... + 1455801.

It is an arithmetic number, because the mean of its divisors is an integer number (50064645675).

Almost surely, 2^398704400021 is an apocalyptic number.

It is an amenable number.

398704400021 is a deficient number, since it is larger than the sum of its proper divisors (1812765379).

398704400021 is a wasteful number, since it uses less digits than its factorization.

398704400021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 311959.

The product of its (nonzero) digits is 48384, while the sum is 38.

The spelling of 398704400021 in words is "three hundred ninety-eight billion, seven hundred four million, four hundred thousand, twenty-one".