398508021 has 12 divisors (see below), whose sum is σ = 575927820. Its totient is φ = 265531200.

The previous prime is 398507981. The next prime is 398508023. The reversal of 398508021 is 120805893.

It can be written as a sum of positive squares in 2 ways, for example, as 73102500 + 325405521 = 8550^2 + 18039^2 .

It is not a de Polignac number, because 398508021 - 2¹⁴ = 398491637 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (398508023) 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 11 ways as a sum of consecutive naturals, for example, 7921 + ... + 29321.

It is an arithmetic number, because the mean of its divisors is an integer number (47993985).

Almost surely, 2^398508021 is an apocalyptic number.

It is an amenable number.

398508021 is a deficient number, since it is larger than the sum of its proper divisors (177419799).

398508021 is a wasteful number, since it uses less digits than its factorization.

398508021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23476 (or 23473 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 36.

The square root of 398508021 is about 19962.6656787113. The cubic root of 398508021 is about 735.8890754430.

The spelling of 398508021 in words is "three hundred ninety-eight million, five hundred eight thousand, twenty-one".