401031391 has 2 divisors, whose sum is σ = 401031392. Its totient is φ = 401031390.

The previous prime is 401031353. The next prime is 401031457. The reversal of 401031391 is 193130104.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 401031391 - 2¹⁵ = 400998623 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (401031331) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 200515695 + 200515696.

It is an arithmetic number, because the mean of its divisors is an integer number (200515696).

Almost surely, 2^401031391 is an apocalyptic number.

401031391 is a deficient number, since it is larger than the sum of its proper divisors (1).

401031391 is an equidigital number, since it uses as much as digits as its factorization.

401031391 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 324, while the sum is 22.

The square root of 401031391 is about 20025.7681750289. The cubic root of 401031391 is about 737.4390356960.

Adding to 401031391 its reverse (193130104), we get a palindrome (594161495).

The spelling of 401031391 in words is "four hundred one million, thirty-one thousand, three hundred ninety-one".