400978394 has 16 divisors (see below), whose sum is σ = 635493600. Its totient is φ = 189226224.

The previous prime is 400978381. The next prime is 400978399. The reversal of 400978394 is 493879004.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (400978399) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9392 + ... + 29835.

It is an arithmetic number, because the mean of its divisors is an integer number (39718350).

Almost surely, 2^400978394 is an apocalyptic number.

400978394 is a deficient number, since it is larger than the sum of its proper divisors (234515206).

400978394 is a wasteful number, since it uses less digits than its factorization.

400978394 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39517.

The product of its (nonzero) digits is 217728, while the sum is 44.

The square root of 400978394 is about 20024.4449111580. Note that the first 3 decimals coincide. The cubic root of 400978394 is about 737.4065496453.

The spelling of 400978394 in words is "four hundred million, nine hundred seventy-eight thousand, three hundred ninety-four".