400386201581 has 2 divisors, whose sum is σ = 400386201582. Its totient is φ = 400386201580.

The previous prime is 400386201569. The next prime is 400386201643. The reversal of 400386201581 is 185102683004.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 344638269481 + 55747932100 = 587059^2 + 236110^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-400386201581 is a prime.

It is a super-2 number, since 2×400386201581² (a number of 24 digits) contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (400386201541) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 200193100790 + 200193100791.

It is an arithmetic number, because the mean of its divisors is an integer number (200193100791).

Almost surely, 2^400386201581 is an apocalyptic number.

It is an amenable number.

400386201581 is a deficient number, since it is larger than the sum of its proper divisors (1).

400386201581 is an equidigital number, since it uses as much as digits as its factorization.

400386201581 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 46080, while the sum is 38.

Adding to 400386201581 its reverse (185102683004), we get a palindrome (585488884585).

The spelling of 400386201581 in words is "four hundred billion, three hundred eighty-six million, two hundred one thousand, five hundred eighty-one".