400409256721 has 16 divisors (see below), whose sum is σ = 421570569600. Its totient is φ = 379770386688.

The previous prime is 400409256701. The next prime is 400409256739. The reversal of 400409256721 is 127652904004.

It is a cyclic number.

It is not a de Polignac number, because 400409256721 - 2¹³ = 400409248529 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (400409256701) 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, 410521 + ... + 984553.

It is an arithmetic number, because the mean of its divisors is an integer number (26348160600).

Almost surely, 2^400409256721 is an apocalyptic number.

It is an amenable number.

400409256721 is a deficient number, since it is larger than the sum of its proper divisors (21161312879).

400409256721 is a wasteful number, since it uses less digits than its factorization.

400409256721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 574488.

The product of its (nonzero) digits is 120960, while the sum is 40.

The spelling of 400409256721 in words is "four hundred billion, four hundred nine million, two hundred fifty-six thousand, seven hundred twenty-one".