398615621 has 4 divisors (see below), whose sum is σ = 401154732. Its totient is φ = 396076512.

The previous prime is 398615617. The next prime is 398615681. The reversal of 398615621 is 126516893.

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 292752100 + 105863521 = 17110^2 + 10289^2 .

It is a cyclic number.

It is not a de Polignac number, because 398615621 - 2² = 398615617 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (398615681) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1269320 + ... + 1269633.

It is an arithmetic number, because the mean of its divisors is an integer number (100288683).

Almost surely, 2^398615621 is an apocalyptic number.

It is an amenable number.

398615621 is a deficient number, since it is larger than the sum of its proper divisors (2539111).

398615621 is a wasteful number, since it uses less digits than its factorization.

398615621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2539110.

The product of its digits is 77760, while the sum is 41.

The square root of 398615621 is about 19965.3605276739. The cubic root of 398615621 is about 735.9553012443.

The spelling of 398615621 in words is "three hundred ninety-eight million, six hundred fifteen thousand, six hundred twenty-one".