400557643 has 4 divisors (see below), whose sum is σ = 406044808. Its totient is φ = 395070480.

The previous prime is 400557637. The next prime is 400557649. The reversal of 400557643 is 346755004.

It is a happy number.

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

It is an interprime number because it is at equal distance from previous prime (400557637) and next prime (400557649).

It is a cyclic number.

It is not a de Polignac number, because 400557643 - 2¹⁷ = 400426571 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 400557599 and 400557608.

It is not an unprimeable number, because it can be changed into a prime (400557649) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2743473 + ... + 2743618.

It is an arithmetic number, because the mean of its divisors is an integer number (101511202).

Almost surely, 2^400557643 is an apocalyptic number.

400557643 is a deficient number, since it is larger than the sum of its proper divisors (5487165).

400557643 is an equidigital number, since it uses as much as digits as its factorization.

400557643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5487164.

The product of its (nonzero) digits is 50400, while the sum is 34.

The square root of 400557643 is about 20013.9362195446. The cubic root of 400557643 is about 737.1485364685.

The spelling of 400557643 in words is "four hundred million, five hundred fifty-seven thousand, six hundred forty-three".