400136405 has 16 divisors (see below), whose sum is σ = 503691264. Its totient is φ = 304571520.

The previous prime is 400136369. The next prime is 400136411. The reversal of 400136405 is 504631004.

It is a happy number.

It is not a de Polignac number, because 400136405 - 2²² = 395942101 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (23).

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 12857 + ... + 31073.

It is an arithmetic number, because the mean of its divisors is an integer number (31480704).

Almost surely, 2^400136405 is an apocalyptic number.

It is an amenable number.

400136405 is a deficient number, since it is larger than the sum of its proper divisors (103554859).

400136405 is a wasteful number, since it uses less digits than its factorization.

400136405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18436.

The product of its (nonzero) digits is 1440, while the sum is 23.

The square root of 400136405 is about 20003.4098343257. The cubic root of 400136405 is about 736.8900435957.

Adding to 400136405 its reverse (504631004), we get a palindrome (904767409).

The spelling of 400136405 in words is "four hundred million, one hundred thirty-six thousand, four hundred five".