398921655 has 32 divisors (see below), whose sum is σ = 704712960. Its totient is φ = 191079680.

The previous prime is 398921599. The next prime is 398921659. The reversal of 398921655 is 556129893.

It is a happy number.

It is not a de Polignac number, because 398921655 - 2⁸ = 398921399 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (398921659) 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 31 ways as a sum of consecutive naturals, for example, 870 + ... + 28259.

It is an arithmetic number, because the mean of its divisors is an integer number (22022280).

Almost surely, 2^398921655 is an apocalyptic number.

398921655 is a deficient number, since it is larger than the sum of its proper divisors (305791305).

398921655 is a wasteful number, since it uses less digits than its factorization.

398921655 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29231.

The product of its digits is 583200, while the sum is 48.

The square root of 398921655 is about 19973.0231812813. The cubic root of 398921655 is about 736.1435943589.

The spelling of 398921655 in words is "three hundred ninety-eight million, nine hundred twenty-one thousand, six hundred fifty-five".