400641645 has 16 divisors (see below), whose sum is σ = 641452032. Its totient is φ = 213533760.

The previous prime is 400641617. The next prime is 400641667. The reversal of 400641645 is 546146004.

It is not a de Polignac number, because 400641645 - 2¹¹ = 400639597 is a prime.

It is a super-3 number, since 3×400641645³ (a number of 27 digits) contains 333 as substring.

It is a Curzon 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, 16915 + ... + 32975.

It is an arithmetic number, because the mean of its divisors is an integer number (40090752).

Almost surely, 2^400641645 is an apocalyptic number.

It is an amenable number.

400641645 is a deficient number, since it is larger than the sum of its proper divisors (240810387).

400641645 is a wasteful number, since it uses less digits than its factorization.

400641645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17732.

The product of its (nonzero) digits is 11520, while the sum is 30.

The square root of 400641645 is about 20016.0346972121. The cubic root of 400641645 is about 737.2000626549.

Adding to 400641645 its reverse (546146004), we get a palindrome (946787649).

The spelling of 400641645 in words is "four hundred million, six hundred forty-one thousand, six hundred forty-five".