398557787 has 4 divisors (see below), whose sum is σ = 399357000. Its totient is φ = 397758576.

The previous prime is 398557781. The next prime is 398557799. The reversal of 398557787 is 787755893.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 398557787 - 2⁶ = 398557723 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (398557781) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 398858 + ... + 399855.

It is an arithmetic number, because the mean of its divisors is an integer number (99839250).

Almost surely, 2^398557787 is an apocalyptic number.

398557787 is a deficient number, since it is larger than the sum of its proper divisors (799213).

398557787 is an equidigital number, since it uses as much as digits as its factorization.

398557787 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 799212.

The product of its digits is 14817600, while the sum is 59.

The square root of 398557787 is about 19963.9121166168. The cubic root of 398557787 is about 735.9197069732.

The spelling of 398557787 in words is "three hundred ninety-eight million, five hundred fifty-seven thousand, seven hundred eighty-seven".