400642324021 has 2 divisors, whose sum is σ = 400642324022. Its totient is φ = 400642324020.

The previous prime is 400642324013. The next prime is 400642324157. The reversal of 400642324021 is 120423246004.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 204384463921 + 196257860100 = 452089^2 + 443010^2 .

It is a cyclic number.

It is not a de Polignac number, because 400642324021 - 2³ = 400642324013 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (400642324001) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 200321162010 + 200321162011.

It is an arithmetic number, because the mean of its divisors is an integer number (200321162011).

Almost surely, 2^400642324021 is an apocalyptic number.

It is an amenable number.

400642324021 is a deficient number, since it is larger than the sum of its proper divisors (1).

400642324021 is an equidigital number, since it uses as much as digits as its factorization.

400642324021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 9216, while the sum is 28.

The spelling of 400642324021 in words is "four hundred billion, six hundred forty-two million, three hundred twenty-four thousand, twenty-one".