400001000 has 64 divisors (see below), whose sum is σ = 1069735680. Its totient is φ = 137140800.

The previous prime is 400000949. The next prime is 400001009. The reversal of 400001000 is 100004.

It is a Harshad number since it is a multiple of its sum of digits (5).

It is a super Niven number, because it is divisible the sum of any subset of its (nonzero) digits.

It is not an unprimeable number, because it can be changed into a prime (400001009) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 21572 + ... + 35571.

It is an arithmetic number, because the mean of its divisors is an integer number (16714620).

Almost surely, 2^400001000 is an apocalyptic number.

400001000 is a gapful number since it is divisible by the number (40) formed by its first and last digit.

It is an amenable number.

400001000 is an abundant number, since it is smaller than the sum of its proper divisors (669734680).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

400001000 is a wasteful number, since it uses less digits than its factorization.

400001000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 57171 (or 57157 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 5.

The square root of 400001000 is about 20000.0249999844. The cubic root of 400001000 is about 736.8069137328.

Adding to 400001000 its reverse (100004), we get a palindrome (400101004).

The spelling of 400001000 in words is "four hundred million, one thousand".