400728321 has 36 divisors (see below), whose sum is σ = 676467792. Its totient is φ = 227921904.

The previous prime is 400728319. The next prime is 400728323. The reversal of 400728321 is 123827004.

It is an interprime number because it is at equal distance from previous prime (400728319) and next prime (400728323).

It is not a de Polignac number, because 400728321 - 2¹ = 400728319 is a prime.

It is not an unprimeable number, because it can be changed into a prime (400728323) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 98106 + ... + 102108.

It is an arithmetic number, because the mean of its divisors is an integer number (18790772).

Almost surely, 2^400728321 is an apocalyptic number.

It is an amenable number.

400728321 is a deficient number, since it is larger than the sum of its proper divisors (275739471).

400728321 is a wasteful number, since it uses less digits than its factorization.

400728321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4250 (or 4240 counting only the distinct ones).

The product of its (nonzero) digits is 2688, while the sum is 27.

The square root of 400728321 is about 20018.1997442327. The cubic root of 400728321 is about 737.2532215032.

The spelling of 400728321 in words is "four hundred million, seven hundred twenty-eight thousand, three hundred twenty-one".