399758978 has 8 divisors (see below), whose sum is σ = 634911372. Its totient is φ = 188121856.

The previous prime is 399758977. The next prime is 399758999. The reversal of 399758978 is 879857993.

It can be written as a sum of positive squares in 2 ways, for example, as 383493889 + 16265089 = 19583^2 + 4033^2 .

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

It is not an unprimeable number, because it can be changed into a prime (399758971) 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, 5878775 + ... + 5878842.

Almost surely, 2^399758978 is an apocalyptic number.

399758978 is a deficient number, since it is larger than the sum of its proper divisors (235152394).

399758978 is a wasteful number, since it uses less digits than its factorization.

399758978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11757636.

The product of its digits is 34292160, while the sum is 65.

The square root of 399758978 is about 19993.9735420451. The cubic root of 399758978 is about 736.6582812210.

The spelling of 399758978 in words is "three hundred ninety-nine million, seven hundred fifty-eight thousand, nine hundred seventy-eight".